From 96a006122b96393f9cd3f4842728ffd7df3bfc6d Mon Sep 17 00:00:00 2001
From: Jay DeLuca <jaydeluca4@gmail.com>
Date: Thu, 30 Apr 2026 15:57:15 -0400
Subject: [PATCH 1/6] Create name just one

Signed-off-by: Jay DeLuca <jaydeluca4@gmail.com>
---
 .../HistogramTextFormatBenchmark.java         | 103 ++++++++++++++++++
 mise.toml                                     |   5 +-
 .../OpenMetrics2TextFormatWriter.java         |   5 +-
 .../OpenMetricsTextFormatWriter.java          |   8 +-
 .../PrometheusTextFormatWriter.java           |   8 +-
 5 files changed, 118 insertions(+), 11 deletions(-)
 create mode 100644 benchmarks/src/main/java/io/prometheus/metrics/benchmarks/HistogramTextFormatBenchmark.java

diff --git a/benchmarks/src/main/java/io/prometheus/metrics/benchmarks/HistogramTextFormatBenchmark.java b/benchmarks/src/main/java/io/prometheus/metrics/benchmarks/HistogramTextFormatBenchmark.java
new file mode 100644
index 000000000..e77af64eb
--- /dev/null
+++ b/benchmarks/src/main/java/io/prometheus/metrics/benchmarks/HistogramTextFormatBenchmark.java
@@ -0,0 +1,103 @@
+package io.prometheus.metrics.benchmarks;
+
+import io.prometheus.metrics.config.EscapingScheme;
+import io.prometheus.metrics.expositionformats.ExpositionFormatWriter;
+import io.prometheus.metrics.expositionformats.OpenMetricsTextFormatWriter;
+import io.prometheus.metrics.expositionformats.PrometheusTextFormatWriter;
+import io.prometheus.metrics.model.snapshots.ClassicHistogramBuckets;
+import io.prometheus.metrics.model.snapshots.HistogramSnapshot;
+import io.prometheus.metrics.model.snapshots.HistogramSnapshot.HistogramDataPointSnapshot;
+import io.prometheus.metrics.model.snapshots.Labels;
+import io.prometheus.metrics.model.snapshots.MetricSnapshots;
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.OutputStream;
+import org.openjdk.jmh.annotations.Benchmark;
+import org.openjdk.jmh.annotations.Scope;
+import org.openjdk.jmh.annotations.State;
+
+/**
+ * Benchmarks for writing a classic histogram (10 label combinations × 12 buckets) to text formats.
+ *
+ * <pre>
+ * Benchmark                                                        Mode  Cnt  Score  Error  Units
+ * HistogramTextFormatBenchmark.openMetricsWriteToByteArray         thrpt
+ * HistogramTextFormatBenchmark.openMetricsWriteToNull              thrpt
+ * HistogramTextFormatBenchmark.prometheusWriteToByteArray          thrpt
+ * HistogramTextFormatBenchmark.prometheusWriteToNull               thrpt
+ * </pre>
+ */
+public class HistogramTextFormatBenchmark {
+
+  private static final MetricSnapshots SNAPSHOTS;
+
+  static {
+    double[] upperBounds = {
+      .005, .01, .025, .05, .1, .25, .5, 1.0, 2.5, 5.0, 10.0, Double.POSITIVE_INFINITY
+    };
+    Number[] counts = {1L, 2L, 3L, 4L, 5L, 6L, 7L, 8L, 9L, 10L, 11L, 12L};
+    ClassicHistogramBuckets buckets = ClassicHistogramBuckets.of(upperBounds, counts);
+
+    HistogramSnapshot.Builder builder =
+        HistogramSnapshot.builder().name("http_request_duration_seconds");
+
+    for (int i = 0; i < 10; i++) {
+      builder.dataPoint(
+          HistogramDataPointSnapshot.builder()
+              .classicHistogramBuckets(buckets)
+              .labels(Labels.of("status", "value_" + i))
+              .sum(123.456)
+              .createdTimestampMillis(1000L)
+              .build());
+    }
+
+    SNAPSHOTS = MetricSnapshots.of(builder.build());
+  }
+
+  private static final ExpositionFormatWriter OPEN_METRICS_TEXT_FORMAT_WRITER =
+      OpenMetricsTextFormatWriter.create();
+  private static final ExpositionFormatWriter PROMETHEUS_TEXT_FORMAT_WRITER =
+      PrometheusTextFormatWriter.create();
+
+  @State(Scope.Benchmark)
+  public static class WriterState {
+
+    final ByteArrayOutputStream byteArrayOutputStream;
+
+    public WriterState() {
+      this.byteArrayOutputStream = new ByteArrayOutputStream();
+    }
+  }
+
+  @Benchmark
+  public OutputStream openMetricsWriteToByteArray(WriterState writerState) throws IOException {
+    ByteArrayOutputStream byteArrayOutputStream = writerState.byteArrayOutputStream;
+    byteArrayOutputStream.reset();
+    OPEN_METRICS_TEXT_FORMAT_WRITER.write(
+        byteArrayOutputStream, SNAPSHOTS, EscapingScheme.ALLOW_UTF8);
+    return byteArrayOutputStream;
+  }
+
+  @Benchmark
+  public OutputStream openMetricsWriteToNull() throws IOException {
+    OutputStream nullOutputStream = TextFormatUtilBenchmark.NullOutputStream.INSTANCE;
+    OPEN_METRICS_TEXT_FORMAT_WRITER.write(nullOutputStream, SNAPSHOTS, EscapingScheme.ALLOW_UTF8);
+    return nullOutputStream;
+  }
+
+  @Benchmark
+  public OutputStream prometheusWriteToByteArray(WriterState writerState) throws IOException {
+    ByteArrayOutputStream byteArrayOutputStream = writerState.byteArrayOutputStream;
+    byteArrayOutputStream.reset();
+    PROMETHEUS_TEXT_FORMAT_WRITER.write(
+        byteArrayOutputStream, SNAPSHOTS, EscapingScheme.ALLOW_UTF8);
+    return byteArrayOutputStream;
+  }
+
+  @Benchmark
+  public OutputStream prometheusWriteToNull() throws IOException {
+    OutputStream nullOutputStream = TextFormatUtilBenchmark.NullOutputStream.INSTANCE;
+    PROMETHEUS_TEXT_FORMAT_WRITER.write(nullOutputStream, SNAPSHOTS, EscapingScheme.ALLOW_UTF8);
+    return nullOutputStream;
+  }
+}
diff --git a/mise.toml b/mise.toml
index 70cfecbaa..cf5cb8657 100644
--- a/mise.toml
+++ b/mise.toml
@@ -59,7 +59,6 @@ run = "./mvnw install -DskipTests -Dcoverage.skip=true"
 
 [tasks."lint"]
 description = "Run all lints"
-raw_args = true
 depends = ["lint:bom"]
 run = "flint run"
 
@@ -95,11 +94,11 @@ run = ["hugo --gc --minify --baseURL ${BASE_URL}/", "echo 'ls ./public/api' && l
 
 [tasks."benchmark:quick"]
 description = "Run benchmarks with reduced iterations (quick smoke test, ~10 min)"
-run = "python3 ./.mise/tasks/update_benchmarks.py --jmh-args '-f 1 -wi 1 -i 3'"
+run = "python3 ./.mise/tasks/update_benchmarks.py --jmh-args '-f 1 -wi 1 -i 3 -prof gc'"
 
 [tasks."benchmark:ci"]
 description = "Run benchmarks with CI configuration (3 forks, 3 warmup, 5 measurement iterations (~60 min total)"
-run = "python3 ./.mise/tasks/update_benchmarks.py --jmh-args '-f 3 -wi 3 -i 5'"
+run = "python3 ./.mise/tasks/update_benchmarks.py --jmh-args '-f 3 -wi 3 -i 5 -prof gc'"
 
 [tasks."benchmark:ci-json"]
 description = "Run benchmarks with CI configuration and JSON output (for workflow/testing)"
diff --git a/prometheus-metrics-exposition-textformats/src/main/java/io/prometheus/metrics/expositionformats/OpenMetrics2TextFormatWriter.java b/prometheus-metrics-exposition-textformats/src/main/java/io/prometheus/metrics/expositionformats/OpenMetrics2TextFormatWriter.java
index 963b18507..19e1e4c93 100644
--- a/prometheus-metrics-exposition-textformats/src/main/java/io/prometheus/metrics/expositionformats/OpenMetrics2TextFormatWriter.java
+++ b/prometheus-metrics-exposition-textformats/src/main/java/io/prometheus/metrics/expositionformats/OpenMetrics2TextFormatWriter.java
@@ -258,6 +258,7 @@ private void writeClassicHistogramDataPoints(
       HistogramSnapshot snapshot,
       EscapingScheme scheme)
       throws IOException {
+    String bucketName = name + "_bucket";
     for (HistogramSnapshot.HistogramDataPointSnapshot data : snapshot.getDataPoints()) {
       ClassicHistogramBuckets buckets = getClassicBuckets(data);
       Exemplars exemplars = data.getExemplars();
@@ -265,7 +266,7 @@ private void writeClassicHistogramDataPoints(
       for (int i = 0; i < buckets.size(); i++) {
         cumulativeCount += buckets.getCount(i);
         writeNameAndLabels(
-            writer, name, "_bucket", data.getLabels(), scheme, "le", buckets.getUpperBound(i));
+            writer, bucketName, null, data.getLabels(), scheme, "le", buckets.getUpperBound(i));
         writeLong(writer, cumulativeCount);
         Exemplar exemplar;
         if (i == 0) {
@@ -636,7 +637,7 @@ private void writeNameAndLabels(
       metricInsideBraces = true;
       writer.write('{');
     }
-    writeName(writer, name + (suffix != null ? suffix : ""), NameType.Metric);
+    writeName(writer, suffix != null ? name + suffix : name, NameType.Metric);
     if (!labels.isEmpty() || additionalLabelName != null) {
       writeLabels(
           writer,
diff --git a/prometheus-metrics-exposition-textformats/src/main/java/io/prometheus/metrics/expositionformats/OpenMetricsTextFormatWriter.java b/prometheus-metrics-exposition-textformats/src/main/java/io/prometheus/metrics/expositionformats/OpenMetricsTextFormatWriter.java
index 1bc7e101f..4cf2068ae 100644
--- a/prometheus-metrics-exposition-textformats/src/main/java/io/prometheus/metrics/expositionformats/OpenMetricsTextFormatWriter.java
+++ b/prometheus-metrics-exposition-textformats/src/main/java/io/prometheus/metrics/expositionformats/OpenMetricsTextFormatWriter.java
@@ -190,6 +190,8 @@ private void writeClassicHistogramBuckets(
       List<HistogramSnapshot.HistogramDataPointSnapshot> dataList,
       EscapingScheme scheme)
       throws IOException {
+    String name = getMetadataName(metadata, scheme);
+    String bucketName = name + "_bucket";
     for (HistogramSnapshot.HistogramDataPointSnapshot data : dataList) {
       ClassicHistogramBuckets buckets = getClassicBuckets(data);
       Exemplars exemplars = data.getExemplars();
@@ -198,8 +200,8 @@ private void writeClassicHistogramBuckets(
         cumulativeCount += buckets.getCount(i);
         writeNameAndLabels(
             writer,
-            getMetadataName(metadata, scheme),
-            "_bucket",
+            bucketName,
+            null,
             data.getLabels(),
             scheme,
             "le",
@@ -409,7 +411,7 @@ private void writeNameAndLabels(
       metricInsideBraces = true;
       writer.write('{');
     }
-    writeName(writer, name + (suffix != null ? suffix : ""), NameType.Metric);
+    writeName(writer, suffix != null ? name + suffix : name, NameType.Metric);
     if (!labels.isEmpty() || additionalLabelName != null) {
       writeLabels(
           writer,
diff --git a/prometheus-metrics-exposition-textformats/src/main/java/io/prometheus/metrics/expositionformats/PrometheusTextFormatWriter.java b/prometheus-metrics-exposition-textformats/src/main/java/io/prometheus/metrics/expositionformats/PrometheusTextFormatWriter.java
index b40dcfdf2..d388810ca 100644
--- a/prometheus-metrics-exposition-textformats/src/main/java/io/prometheus/metrics/expositionformats/PrometheusTextFormatWriter.java
+++ b/prometheus-metrics-exposition-textformats/src/main/java/io/prometheus/metrics/expositionformats/PrometheusTextFormatWriter.java
@@ -204,6 +204,8 @@ private void writeHistogram(Writer writer, HistogramSnapshot snapshot, EscapingS
       throws IOException {
     MetricMetadata metadata = snapshot.getMetadata();
     writeMetadata(writer, "", "histogram", metadata, scheme);
+    String name = getMetadataName(metadata, scheme);
+    String bucketName = name + "_bucket";
     for (HistogramSnapshot.HistogramDataPointSnapshot data : snapshot.getDataPoints()) {
       ClassicHistogramBuckets buckets = getClassicBuckets(data);
       long cumulativeCount = 0;
@@ -211,8 +213,8 @@ private void writeHistogram(Writer writer, HistogramSnapshot snapshot, EscapingS
         cumulativeCount += buckets.getCount(i);
         writeNameAndLabels(
             writer,
-            getMetadataName(metadata, scheme),
-            "_bucket",
+            bucketName,
+            null,
             data.getLabels(),
             scheme,
             "le",
@@ -405,7 +407,7 @@ private void writeNameAndLabels(
       metricInsideBraces = true;
       writer.write('{');
     }
-    writeName(writer, name + (suffix != null ? suffix : ""), NameType.Metric);
+    writeName(writer, suffix != null ? name + suffix : name, NameType.Metric);
     if (!labels.isEmpty() || additionalLabelName != null) {
       writeLabels(
           writer, labels, additionalLabelName, additionalLabelValue, metricInsideBraces, scheme);

From 29f7c73f550745bae75a988d51124fb1891eb938 Mon Sep 17 00:00:00 2001
From: Jay DeLuca <jaydeluca4@gmail.com>
Date: Thu, 30 Apr 2026 16:52:25 -0400
Subject: [PATCH 2/6] add benchmark

Signed-off-by: Jay DeLuca <jaydeluca4@gmail.com>
---
 .../HistogramTextFormatBenchmark.java         | 26 +++++++++++++++----
 1 file changed, 21 insertions(+), 5 deletions(-)

diff --git a/benchmarks/src/main/java/io/prometheus/metrics/benchmarks/HistogramTextFormatBenchmark.java b/benchmarks/src/main/java/io/prometheus/metrics/benchmarks/HistogramTextFormatBenchmark.java
index e77af64eb..e2cce19db 100644
--- a/benchmarks/src/main/java/io/prometheus/metrics/benchmarks/HistogramTextFormatBenchmark.java
+++ b/benchmarks/src/main/java/io/prometheus/metrics/benchmarks/HistogramTextFormatBenchmark.java
@@ -20,11 +20,27 @@
  * Benchmarks for writing a classic histogram (10 label combinations × 12 buckets) to text formats.
  *
  * <pre>
- * Benchmark                                                        Mode  Cnt  Score  Error  Units
- * HistogramTextFormatBenchmark.openMetricsWriteToByteArray         thrpt
- * HistogramTextFormatBenchmark.openMetricsWriteToNull              thrpt
- * HistogramTextFormatBenchmark.prometheusWriteToByteArray          thrpt
- * HistogramTextFormatBenchmark.prometheusWriteToNull               thrpt
+ * Benchmark                                                                     Mode  Cnt       Score        Error   Units
+ * HistogramTextFormatBenchmark.openMetricsWriteToByteArray                     thrpt    3   37567.116 ±  14566.571   ops/s
+ * HistogramTextFormatBenchmark.openMetricsWriteToByteArray:gc.alloc.rate       thrpt    3    1466.289 ±    568.584  MB/sec
+ * HistogramTextFormatBenchmark.openMetricsWriteToByteArray:gc.alloc.rate.norm  thrpt    3   40928.019 ±      0.006    B/op
+ * HistogramTextFormatBenchmark.openMetricsWriteToByteArray:gc.count            thrpt    3     147.000               counts
+ * HistogramTextFormatBenchmark.openMetricsWriteToByteArray:gc.time             thrpt    3      77.000                   ms
+ * HistogramTextFormatBenchmark.openMetricsWriteToNull                          thrpt    3   36179.016 ±   1149.646   ops/s
+ * HistogramTextFormatBenchmark.openMetricsWriteToNull:gc.alloc.rate            thrpt    3    1412.112 ±     44.791  MB/sec
+ * HistogramTextFormatBenchmark.openMetricsWriteToNull:gc.alloc.rate.norm       thrpt    3   40928.019 ±      0.001    B/op
+ * HistogramTextFormatBenchmark.openMetricsWriteToNull:gc.count                 thrpt    3     142.000               counts
+ * HistogramTextFormatBenchmark.openMetricsWriteToNull:gc.time                  thrpt    3      74.000                   ms
+ * HistogramTextFormatBenchmark.prometheusWriteToByteArray                      thrpt    3   36616.472 ±   5189.952   ops/s
+ * HistogramTextFormatBenchmark.prometheusWriteToByteArray:gc.alloc.rate        thrpt    3    1434.773 ±    203.524  MB/sec
+ * HistogramTextFormatBenchmark.prometheusWriteToByteArray:gc.alloc.rate.norm   thrpt    3   41088.019 ±      0.003    B/op
+ * HistogramTextFormatBenchmark.prometheusWriteToByteArray:gc.count             thrpt    3     144.000               counts
+ * HistogramTextFormatBenchmark.prometheusWriteToByteArray:gc.time              thrpt    3      73.000                   ms
+ * HistogramTextFormatBenchmark.prometheusWriteToNull                           thrpt    3   36357.284 ±   4298.616   ops/s
+ * HistogramTextFormatBenchmark.prometheusWriteToNull:gc.alloc.rate             thrpt    3    1424.614 ±    168.607  MB/sec
+ * HistogramTextFormatBenchmark.prometheusWriteToNull:gc.alloc.rate.norm        thrpt    3   41088.019 ±      0.003    B/op
+ * HistogramTextFormatBenchmark.prometheusWriteToNull:gc.count                  thrpt    3     143.000               counts
+ * HistogramTextFormatBenchmark.prometheusWriteToNull:gc.time                   thrpt    3      73.000                   ms
  * </pre>
  */
 public class HistogramTextFormatBenchmark {

From 94448484a3a7a47e9af06e47890918f42dda14d7 Mon Sep 17 00:00:00 2001
From: Jay DeLuca <jaydeluca4@gmail.com>
Date: Fri, 1 May 2026 08:11:43 -0400
Subject: [PATCH 3/6] more allocations avoided

Signed-off-by: Jay DeLuca <jaydeluca4@gmail.com>
---
 .../HistogramTextFormatBenchmark.java         | 81 ++++++++++++-------
 .../OpenMetrics2TextFormatWriter.java         |  5 ++
 .../OpenMetricsTextFormatWriter.java          | 54 ++++++-------
 .../PrometheusTextFormatWriter.java           | 55 +++++++------
 .../expositionformats/TextFormatUtil.java     | 24 ++++--
 5 files changed, 134 insertions(+), 85 deletions(-)

diff --git a/benchmarks/src/main/java/io/prometheus/metrics/benchmarks/HistogramTextFormatBenchmark.java b/benchmarks/src/main/java/io/prometheus/metrics/benchmarks/HistogramTextFormatBenchmark.java
index e2cce19db..0ef1bbc2a 100644
--- a/benchmarks/src/main/java/io/prometheus/metrics/benchmarks/HistogramTextFormatBenchmark.java
+++ b/benchmarks/src/main/java/io/prometheus/metrics/benchmarks/HistogramTextFormatBenchmark.java
@@ -1,7 +1,6 @@
 package io.prometheus.metrics.benchmarks;
 
 import io.prometheus.metrics.config.EscapingScheme;
-import io.prometheus.metrics.expositionformats.ExpositionFormatWriter;
 import io.prometheus.metrics.expositionformats.OpenMetricsTextFormatWriter;
 import io.prometheus.metrics.expositionformats.PrometheusTextFormatWriter;
 import io.prometheus.metrics.model.snapshots.ClassicHistogramBuckets;
@@ -9,39 +8,31 @@
 import io.prometheus.metrics.model.snapshots.HistogramSnapshot.HistogramDataPointSnapshot;
 import io.prometheus.metrics.model.snapshots.Labels;
 import io.prometheus.metrics.model.snapshots.MetricSnapshots;
+import java.io.BufferedWriter;
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.OutputStream;
+import java.io.OutputStreamWriter;
+import java.io.Writer;
+import java.nio.charset.StandardCharsets;
 import org.openjdk.jmh.annotations.Benchmark;
 import org.openjdk.jmh.annotations.Scope;
 import org.openjdk.jmh.annotations.State;
 
 /**
- * Benchmarks for writing a classic histogram (10 label combinations × 12 buckets) to text formats.
+ * Benchmarks for writing a classic histogram (10 label combinations × 12 buckets) to text
+ * formats.
  *
- * <pre>
- * Benchmark                                                                     Mode  Cnt       Score        Error   Units
- * HistogramTextFormatBenchmark.openMetricsWriteToByteArray                     thrpt    3   37567.116 ±  14566.571   ops/s
- * HistogramTextFormatBenchmark.openMetricsWriteToByteArray:gc.alloc.rate       thrpt    3    1466.289 ±    568.584  MB/sec
- * HistogramTextFormatBenchmark.openMetricsWriteToByteArray:gc.alloc.rate.norm  thrpt    3   40928.019 ±      0.006    B/op
- * HistogramTextFormatBenchmark.openMetricsWriteToByteArray:gc.count            thrpt    3     147.000               counts
- * HistogramTextFormatBenchmark.openMetricsWriteToByteArray:gc.time             thrpt    3      77.000                   ms
- * HistogramTextFormatBenchmark.openMetricsWriteToNull                          thrpt    3   36179.016 ±   1149.646   ops/s
- * HistogramTextFormatBenchmark.openMetricsWriteToNull:gc.alloc.rate            thrpt    3    1412.112 ±     44.791  MB/sec
- * HistogramTextFormatBenchmark.openMetricsWriteToNull:gc.alloc.rate.norm       thrpt    3   40928.019 ±      0.001    B/op
- * HistogramTextFormatBenchmark.openMetricsWriteToNull:gc.count                 thrpt    3     142.000               counts
- * HistogramTextFormatBenchmark.openMetricsWriteToNull:gc.time                  thrpt    3      74.000                   ms
- * HistogramTextFormatBenchmark.prometheusWriteToByteArray                      thrpt    3   36616.472 ±   5189.952   ops/s
- * HistogramTextFormatBenchmark.prometheusWriteToByteArray:gc.alloc.rate        thrpt    3    1434.773 ±    203.524  MB/sec
- * HistogramTextFormatBenchmark.prometheusWriteToByteArray:gc.alloc.rate.norm   thrpt    3   41088.019 ±      0.003    B/op
- * HistogramTextFormatBenchmark.prometheusWriteToByteArray:gc.count             thrpt    3     144.000               counts
- * HistogramTextFormatBenchmark.prometheusWriteToByteArray:gc.time              thrpt    3      73.000                   ms
- * HistogramTextFormatBenchmark.prometheusWriteToNull                           thrpt    3   36357.284 ±   4298.616   ops/s
- * HistogramTextFormatBenchmark.prometheusWriteToNull:gc.alloc.rate             thrpt    3    1424.614 ±    168.607  MB/sec
- * HistogramTextFormatBenchmark.prometheusWriteToNull:gc.alloc.rate.norm        thrpt    3   41088.019 ±      0.003    B/op
- * HistogramTextFormatBenchmark.prometheusWriteToNull:gc.count                  thrpt    3     143.000               counts
- * HistogramTextFormatBenchmark.prometheusWriteToNull:gc.time                   thrpt    3      73.000                   ms
- * </pre>
+ * <p>Two variants per format:
+ *
+ * <ul>
+ *   <li>{@code writeToByteArray} — OutputStream path, new BufferedWriter created per call.
+ *   <li>{@code reusingWriter} — Writer path, BufferedWriter reused across calls.
+ * </ul>
+ *
+ * <p>Baseline (before allocation optimizations): ~41 KB/op for both Prometheus and OpenMetrics
+ * formats, dominated by the per-call BufferedWriter buffer (~16 KB) and number-to-string
+ * conversions.
  */
 public class HistogramTextFormatBenchmark {
 
@@ -70,9 +61,9 @@ public class HistogramTextFormatBenchmark {
     SNAPSHOTS = MetricSnapshots.of(builder.build());
   }
 
-  private static final ExpositionFormatWriter OPEN_METRICS_TEXT_FORMAT_WRITER =
+  private static final OpenMetricsTextFormatWriter OPEN_METRICS_TEXT_FORMAT_WRITER =
       OpenMetricsTextFormatWriter.create();
-  private static final ExpositionFormatWriter PROMETHEUS_TEXT_FORMAT_WRITER =
+  private static final PrometheusTextFormatWriter PROMETHEUS_TEXT_FORMAT_WRITER =
       PrometheusTextFormatWriter.create();
 
   @State(Scope.Benchmark)
@@ -85,6 +76,26 @@ public WriterState() {
     }
   }
 
+  @State(Scope.Benchmark)
+  public static class ReusableWriterState {
+
+    final ByteArrayOutputStream openMetricsByteArrayOutputStream;
+    final ByteArrayOutputStream prometheusByteArrayOutputStream;
+    final BufferedWriter openMetricsWriter;
+    final BufferedWriter prometheusWriter;
+
+    public ReusableWriterState() {
+      this.openMetricsByteArrayOutputStream = new ByteArrayOutputStream();
+      this.prometheusByteArrayOutputStream = new ByteArrayOutputStream();
+      this.openMetricsWriter =
+          new BufferedWriter(
+              new OutputStreamWriter(openMetricsByteArrayOutputStream, StandardCharsets.UTF_8));
+      this.prometheusWriter =
+          new BufferedWriter(
+              new OutputStreamWriter(prometheusByteArrayOutputStream, StandardCharsets.UTF_8));
+    }
+  }
+
   @Benchmark
   public OutputStream openMetricsWriteToByteArray(WriterState writerState) throws IOException {
     ByteArrayOutputStream byteArrayOutputStream = writerState.byteArrayOutputStream;
@@ -101,6 +112,14 @@ public OutputStream openMetricsWriteToNull() throws IOException {
     return nullOutputStream;
   }
 
+  @Benchmark
+  public Writer openMetricsReusingWriter(ReusableWriterState state) throws IOException {
+    state.openMetricsByteArrayOutputStream.reset();
+    OPEN_METRICS_TEXT_FORMAT_WRITER.write(
+        state.openMetricsWriter, SNAPSHOTS, EscapingScheme.ALLOW_UTF8);
+    return state.openMetricsWriter;
+  }
+
   @Benchmark
   public OutputStream prometheusWriteToByteArray(WriterState writerState) throws IOException {
     ByteArrayOutputStream byteArrayOutputStream = writerState.byteArrayOutputStream;
@@ -116,4 +135,12 @@ public OutputStream prometheusWriteToNull() throws IOException {
     PROMETHEUS_TEXT_FORMAT_WRITER.write(nullOutputStream, SNAPSHOTS, EscapingScheme.ALLOW_UTF8);
     return nullOutputStream;
   }
+
+  @Benchmark
+  public Writer prometheusReusingWriter(ReusableWriterState state) throws IOException {
+    state.prometheusByteArrayOutputStream.reset();
+    PROMETHEUS_TEXT_FORMAT_WRITER.write(
+        state.prometheusWriter, SNAPSHOTS, EscapingScheme.ALLOW_UTF8);
+    return state.prometheusWriter;
+  }
 }
diff --git a/prometheus-metrics-exposition-textformats/src/main/java/io/prometheus/metrics/expositionformats/OpenMetrics2TextFormatWriter.java b/prometheus-metrics-exposition-textformats/src/main/java/io/prometheus/metrics/expositionformats/OpenMetrics2TextFormatWriter.java
index 19e1e4c93..ddd764786 100644
--- a/prometheus-metrics-exposition-textformats/src/main/java/io/prometheus/metrics/expositionformats/OpenMetrics2TextFormatWriter.java
+++ b/prometheus-metrics-exposition-textformats/src/main/java/io/prometheus/metrics/expositionformats/OpenMetrics2TextFormatWriter.java
@@ -144,6 +144,11 @@ public OpenMetrics2Properties getOpenMetrics2Properties() {
   public void write(OutputStream out, MetricSnapshots metricSnapshots, EscapingScheme scheme)
       throws IOException {
     Writer writer = new BufferedWriter(new OutputStreamWriter(out, StandardCharsets.UTF_8));
+    write(writer, metricSnapshots, scheme);
+  }
+
+  public void write(Writer writer, MetricSnapshots metricSnapshots, EscapingScheme scheme)
+      throws IOException {
     MetricSnapshots merged = TextFormatUtil.mergeDuplicates(metricSnapshots);
     for (MetricSnapshot s : merged) {
       MetricSnapshot snapshot = SnapshotEscaper.escapeMetricSnapshot(s, scheme);
diff --git a/prometheus-metrics-exposition-textformats/src/main/java/io/prometheus/metrics/expositionformats/OpenMetricsTextFormatWriter.java b/prometheus-metrics-exposition-textformats/src/main/java/io/prometheus/metrics/expositionformats/OpenMetricsTextFormatWriter.java
index 4cf2068ae..eeebad40c 100644
--- a/prometheus-metrics-exposition-textformats/src/main/java/io/prometheus/metrics/expositionformats/OpenMetricsTextFormatWriter.java
+++ b/prometheus-metrics-exposition-textformats/src/main/java/io/prometheus/metrics/expositionformats/OpenMetricsTextFormatWriter.java
@@ -114,6 +114,11 @@ public String getContentType() {
   public void write(OutputStream out, MetricSnapshots metricSnapshots, EscapingScheme scheme)
       throws IOException {
     Writer writer = new BufferedWriter(new OutputStreamWriter(out, StandardCharsets.UTF_8));
+    write(writer, metricSnapshots, scheme);
+  }
+
+  public void write(Writer writer, MetricSnapshots metricSnapshots, EscapingScheme scheme)
+      throws IOException {
     MetricSnapshots merged = TextFormatUtil.mergeDuplicates(metricSnapshots);
     for (MetricSnapshot s : merged) {
       MetricSnapshot snapshot = SnapshotEscaper.escapeMetricSnapshot(s, scheme);
@@ -157,8 +162,9 @@ private void writeGauge(Writer writer, GaugeSnapshot snapshot, EscapingScheme sc
       throws IOException {
     MetricMetadata metadata = snapshot.getMetadata();
     writeMetadata(writer, "gauge", metadata, scheme);
+    String name = getMetadataName(metadata, scheme);
     for (GaugeSnapshot.GaugeDataPointSnapshot data : snapshot.getDataPoints()) {
-      writeNameAndLabels(writer, getMetadataName(metadata, scheme), null, data.getLabels(), scheme);
+      writeNameAndLabels(writer, name, null, data.getLabels(), scheme);
       writeDouble(writer, data.getValue());
       if (exemplarsOnAllMetricTypesEnabled) {
         writeScrapeTimestampAndExemplar(writer, data, data.getExemplar(), scheme);
@@ -192,6 +198,8 @@ private void writeClassicHistogramBuckets(
       throws IOException {
     String name = getMetadataName(metadata, scheme);
     String bucketName = name + "_bucket";
+    String countName = name + countSuffix;
+    String sumName = name + sumSuffix;
     for (HistogramSnapshot.HistogramDataPointSnapshot data : dataList) {
       ClassicHistogramBuckets buckets = getClassicBuckets(data);
       Exemplars exemplars = data.getExemplars();
@@ -217,9 +225,9 @@ private void writeClassicHistogramBuckets(
       }
       // In OpenMetrics format, histogram _count and _sum are either both present or both absent.
       if (data.hasCount() && data.hasSum()) {
-        writeCountAndSum(writer, metadata, data, countSuffix, sumSuffix, exemplars, scheme);
+        writeCountAndSum(writer, countName, sumName, data, exemplars, scheme);
       }
-      writeCreated(writer, metadata, data, scheme);
+      writeCreated(writer, name, data, scheme);
     }
   }
 
@@ -237,6 +245,9 @@ void writeSummary(Writer writer, SummarySnapshot snapshot, EscapingScheme scheme
       throws IOException {
     boolean metadataWritten = false;
     MetricMetadata metadata = snapshot.getMetadata();
+    String name = getMetadataName(metadata, scheme);
+    String countName = name + "_count";
+    String sumName = name + "_sum";
     for (SummarySnapshot.SummaryDataPointSnapshot data : snapshot.getDataPoints()) {
       if (data.getQuantiles().size() == 0 && !data.hasCount() && !data.hasSum()) {
         continue;
@@ -254,13 +265,7 @@ void writeSummary(Writer writer, SummarySnapshot snapshot, EscapingScheme scheme
       int exemplarIndex = 1;
       for (Quantile quantile : data.getQuantiles()) {
         writeNameAndLabels(
-            writer,
-            getMetadataName(metadata, scheme),
-            null,
-            data.getLabels(),
-            scheme,
-            "quantile",
-            quantile.getQuantile());
+            writer, name, null, data.getLabels(), scheme, "quantile", quantile.getQuantile());
         writeDouble(writer, quantile.getValue());
         if (exemplars.size() > 0 && exemplarsOnAllMetricTypesEnabled) {
           exemplarIndex = (exemplarIndex + 1) % exemplars.size();
@@ -270,8 +275,8 @@ void writeSummary(Writer writer, SummarySnapshot snapshot, EscapingScheme scheme
         }
       }
       // Unlike histograms, summaries can have only a count or only a sum according to OpenMetrics.
-      writeCountAndSum(writer, metadata, data, "_count", "_sum", exemplars, scheme);
-      writeCreated(writer, metadata, data, scheme);
+      writeCountAndSum(writer, countName, sumName, data, exemplars, scheme);
+      writeCreated(writer, name, data, scheme);
     }
   }
 
@@ -292,9 +297,10 @@ private void writeStateSet(Writer writer, StateSetSnapshot snapshot, EscapingSch
       throws IOException {
     MetricMetadata metadata = snapshot.getMetadata();
     writeMetadata(writer, "stateset", metadata, scheme);
+    String name = getMetadataName(metadata, scheme);
     for (StateSetSnapshot.StateSetDataPointSnapshot data : snapshot.getDataPoints()) {
       for (int i = 0; i < data.size(); i++) {
-        writer.write(getMetadataName(metadata, scheme));
+        writer.write(name);
         writer.write('{');
         Labels labels = data.getLabels();
         for (int j = 0; j < labels.size(); j++) {
@@ -309,7 +315,7 @@ private void writeStateSet(Writer writer, StateSetSnapshot snapshot, EscapingSch
         if (!labels.isEmpty()) {
           writer.write(",");
         }
-        writer.write(getMetadataName(metadata, scheme));
+        writer.write(name);
         writer.write("=\"");
         writeEscapedString(writer, data.getName(i));
         writer.write("\"} ");
@@ -327,8 +333,9 @@ private void writeUnknown(Writer writer, UnknownSnapshot snapshot, EscapingSchem
       throws IOException {
     MetricMetadata metadata = snapshot.getMetadata();
     writeMetadata(writer, "unknown", metadata, scheme);
+    String name = getMetadataName(metadata, scheme);
     for (UnknownSnapshot.UnknownDataPointSnapshot data : snapshot.getDataPoints()) {
-      writeNameAndLabels(writer, getMetadataName(metadata, scheme), null, data.getLabels(), scheme);
+      writeNameAndLabels(writer, name, null, data.getLabels(), scheme);
       writeDouble(writer, data.getValue());
       if (exemplarsOnAllMetricTypesEnabled) {
         writeScrapeTimestampAndExemplar(writer, data, data.getExemplar(), scheme);
@@ -340,16 +347,14 @@ private void writeUnknown(Writer writer, UnknownSnapshot snapshot, EscapingSchem
 
   private void writeCountAndSum(
       Writer writer,
-      MetricMetadata metadata,
+      String countName,
+      String sumName,
       DistributionDataPointSnapshot data,
-      String countSuffix,
-      String sumSuffix,
       Exemplars exemplars,
       EscapingScheme scheme)
       throws IOException {
     if (data.hasCount()) {
-      writeNameAndLabels(
-          writer, getMetadataName(metadata, scheme), countSuffix, data.getLabels(), scheme);
+      writeNameAndLabels(writer, countName, null, data.getLabels(), scheme);
       writeLong(writer, data.getCount());
       if (exemplarsOnAllMetricTypesEnabled) {
         writeScrapeTimestampAndExemplar(writer, data, exemplars.getLatest(), scheme);
@@ -358,19 +363,12 @@ private void writeCountAndSum(
       }
     }
     if (data.hasSum()) {
-      writeNameAndLabels(
-          writer, getMetadataName(metadata, scheme), sumSuffix, data.getLabels(), scheme);
+      writeNameAndLabels(writer, sumName, null, data.getLabels(), scheme);
       writeDouble(writer, data.getSum());
       writeScrapeTimestampAndExemplar(writer, data, null, scheme);
     }
   }
 
-  private void writeCreated(
-      Writer writer, MetricMetadata metadata, DataPointSnapshot data, EscapingScheme scheme)
-      throws IOException {
-    writeCreated(writer, getMetadataName(metadata, scheme), data, scheme);
-  }
-
   private void writeCreated(
       Writer writer, String baseName, DataPointSnapshot data, EscapingScheme scheme)
       throws IOException {
diff --git a/prometheus-metrics-exposition-textformats/src/main/java/io/prometheus/metrics/expositionformats/PrometheusTextFormatWriter.java b/prometheus-metrics-exposition-textformats/src/main/java/io/prometheus/metrics/expositionformats/PrometheusTextFormatWriter.java
index d388810ca..2b68919c9 100644
--- a/prometheus-metrics-exposition-textformats/src/main/java/io/prometheus/metrics/expositionformats/PrometheusTextFormatWriter.java
+++ b/prometheus-metrics-exposition-textformats/src/main/java/io/prometheus/metrics/expositionformats/PrometheusTextFormatWriter.java
@@ -112,10 +112,15 @@ public String getContentType() {
   @Override
   public void write(OutputStream out, MetricSnapshots metricSnapshots, EscapingScheme scheme)
       throws IOException {
+    Writer writer = new BufferedWriter(new OutputStreamWriter(out, StandardCharsets.UTF_8));
+    write(writer, metricSnapshots, scheme);
+  }
+
+  public void write(Writer writer, MetricSnapshots metricSnapshots, EscapingScheme scheme)
+      throws IOException {
     // See https://prometheus.io/docs/instrumenting/exposition_formats/
     // "unknown", "gauge", "counter", "stateset", "info", "histogram", "gaugehistogram", and
     // "summary".
-    Writer writer = new BufferedWriter(new OutputStreamWriter(out, StandardCharsets.UTF_8));
     MetricSnapshots merged = TextFormatUtil.mergeDuplicates(metricSnapshots);
     for (MetricSnapshot s : merged) {
       MetricSnapshot snapshot = escapeMetricSnapshot(s, scheme);
@@ -193,8 +198,9 @@ private void writeGauge(Writer writer, GaugeSnapshot snapshot, EscapingScheme sc
       throws IOException {
     MetricMetadata metadata = snapshot.getMetadata();
     writeMetadata(writer, "", "gauge", metadata, scheme);
+    String name = getMetadataName(metadata, scheme);
     for (GaugeSnapshot.GaugeDataPointSnapshot data : snapshot.getDataPoints()) {
-      writeNameAndLabels(writer, getMetadataName(metadata, scheme), null, data.getLabels(), scheme);
+      writeNameAndLabels(writer, name, null, data.getLabels(), scheme);
       writeDouble(writer, data.getValue());
       writeScrapeTimestampAndNewline(writer, data);
     }
@@ -206,6 +212,8 @@ private void writeHistogram(Writer writer, HistogramSnapshot snapshot, EscapingS
     writeMetadata(writer, "", "histogram", metadata, scheme);
     String name = getMetadataName(metadata, scheme);
     String bucketName = name + "_bucket";
+    String countName = name + "_count";
+    String sumName = name + "_sum";
     for (HistogramSnapshot.HistogramDataPointSnapshot data : snapshot.getDataPoints()) {
       ClassicHistogramBuckets buckets = getClassicBuckets(data);
       long cumulativeCount = 0;
@@ -224,14 +232,12 @@ private void writeHistogram(Writer writer, HistogramSnapshot snapshot, EscapingS
       }
       if (!snapshot.isGaugeHistogram()) {
         if (data.hasCount()) {
-          writeNameAndLabels(
-              writer, getMetadataName(metadata, scheme), "_count", data.getLabels(), scheme);
+          writeNameAndLabels(writer, countName, null, data.getLabels(), scheme);
           writeLong(writer, data.getCount());
           writeScrapeTimestampAndNewline(writer, data);
         }
         if (data.hasSum()) {
-          writeNameAndLabels(
-              writer, getMetadataName(metadata, scheme), "_sum", data.getLabels(), scheme);
+          writeNameAndLabels(writer, sumName, null, data.getLabels(), scheme);
           writeDouble(writer, data.getSum());
           writeScrapeTimestampAndNewline(writer, data);
         }
@@ -257,6 +263,9 @@ private void writeGaugeCountSum(
       throws IOException {
     // Prometheus text format does not support gaugehistogram's _gcount and _gsum.
     // So we append _gcount and _gsum as gauge metrics.
+    String baseName = getMetadataName(metadata, scheme);
+    String gaugeCountName = baseName + "_gcount";
+    String gaugeSumName = baseName + "_gsum";
     boolean metadataWritten = false;
     for (HistogramSnapshot.HistogramDataPointSnapshot data : snapshot.getDataPoints()) {
       if (data.hasCount()) {
@@ -264,8 +273,7 @@ private void writeGaugeCountSum(
           writeMetadata(writer, "_gcount", "gauge", metadata, scheme);
           metadataWritten = true;
         }
-        writeNameAndLabels(
-            writer, getMetadataName(metadata, scheme), "_gcount", data.getLabels(), scheme);
+        writeNameAndLabels(writer, gaugeCountName, null, data.getLabels(), scheme);
         writeLong(writer, data.getCount());
         writeScrapeTimestampAndNewline(writer, data);
       }
@@ -277,8 +285,7 @@ private void writeGaugeCountSum(
           writeMetadata(writer, "_gsum", "gauge", metadata, scheme);
           metadataWritten = true;
         }
-        writeNameAndLabels(
-            writer, getMetadataName(metadata, scheme), "_gsum", data.getLabels(), scheme);
+        writeNameAndLabels(writer, gaugeSumName, null, data.getLabels(), scheme);
         writeDouble(writer, data.getSum());
         writeScrapeTimestampAndNewline(writer, data);
       }
@@ -289,6 +296,9 @@ private void writeSummary(Writer writer, SummarySnapshot snapshot, EscapingSchem
       throws IOException {
     boolean metadataWritten = false;
     MetricMetadata metadata = snapshot.getMetadata();
+    String name = getMetadataName(metadata, scheme);
+    String countName = name + "_count";
+    String sumName = name + "_sum";
     for (SummarySnapshot.SummaryDataPointSnapshot data : snapshot.getDataPoints()) {
       if (data.getQuantiles().size() == 0 && !data.hasCount() && !data.hasSum()) {
         continue;
@@ -299,25 +309,17 @@ private void writeSummary(Writer writer, SummarySnapshot snapshot, EscapingSchem
       }
       for (Quantile quantile : data.getQuantiles()) {
         writeNameAndLabels(
-            writer,
-            getMetadataName(metadata, scheme),
-            null,
-            data.getLabels(),
-            scheme,
-            "quantile",
-            quantile.getQuantile());
+            writer, name, null, data.getLabels(), scheme, "quantile", quantile.getQuantile());
         writeDouble(writer, quantile.getValue());
         writeScrapeTimestampAndNewline(writer, data);
       }
       if (data.hasCount()) {
-        writeNameAndLabels(
-            writer, getMetadataName(metadata, scheme), "_count", data.getLabels(), scheme);
+        writeNameAndLabels(writer, countName, null, data.getLabels(), scheme);
         writeLong(writer, data.getCount());
         writeScrapeTimestampAndNewline(writer, data);
       }
       if (data.hasSum()) {
-        writeNameAndLabels(
-            writer, getMetadataName(metadata, scheme), "_sum", data.getLabels(), scheme);
+        writeNameAndLabels(writer, sumName, null, data.getLabels(), scheme);
         writeDouble(writer, data.getSum());
         writeScrapeTimestampAndNewline(writer, data);
       }
@@ -340,9 +342,10 @@ private void writeStateSet(Writer writer, StateSetSnapshot snapshot, EscapingSch
       throws IOException {
     MetricMetadata metadata = snapshot.getMetadata();
     writeMetadata(writer, "", "gauge", metadata, scheme);
+    String name = getMetadataName(metadata, scheme);
     for (StateSetSnapshot.StateSetDataPointSnapshot data : snapshot.getDataPoints()) {
       for (int i = 0; i < data.size(); i++) {
-        writer.write(getMetadataName(metadata, scheme));
+        writer.write(name);
         writer.write('{');
         for (int j = 0; j < data.getLabels().size(); j++) {
           if (j > 0) {
@@ -356,7 +359,7 @@ private void writeStateSet(Writer writer, StateSetSnapshot snapshot, EscapingSch
         if (!data.getLabels().isEmpty()) {
           writer.write(",");
         }
-        writer.write(getMetadataName(metadata, scheme));
+        writer.write(name);
         writer.write("=\"");
         writeEscapedString(writer, data.getName(i));
         writer.write("\"} ");
@@ -374,8 +377,9 @@ private void writeUnknown(Writer writer, UnknownSnapshot snapshot, EscapingSchem
       throws IOException {
     MetricMetadata metadata = snapshot.getMetadata();
     writeMetadata(writer, "", "untyped", metadata, scheme);
+    String name = getMetadataName(metadata, scheme);
     for (UnknownSnapshot.UnknownDataPointSnapshot data : snapshot.getDataPoints()) {
-      writeNameAndLabels(writer, getMetadataName(metadata, scheme), null, data.getLabels(), scheme);
+      writeNameAndLabels(writer, name, null, data.getLabels(), scheme);
       writeDouble(writer, data.getValue());
       writeScrapeTimestampAndNewline(writer, data);
     }
@@ -424,7 +428,8 @@ private void writeMetadata(
       MetricMetadata metadata,
       EscapingScheme scheme)
       throws IOException {
-    String name = getMetadataName(metadata, scheme) + (suffix != null ? suffix : "");
+    String baseName = getMetadataName(metadata, scheme);
+    String name = suffix != null ? baseName + suffix : baseName;
     if (metadata.getHelp() != null && !metadata.getHelp().isEmpty()) {
       writer.write("# HELP ");
       writeName(writer, name, NameType.Metric);
diff --git a/prometheus-metrics-exposition-textformats/src/main/java/io/prometheus/metrics/expositionformats/TextFormatUtil.java b/prometheus-metrics-exposition-textformats/src/main/java/io/prometheus/metrics/expositionformats/TextFormatUtil.java
index 5f5f05e8b..8cfed2b29 100644
--- a/prometheus-metrics-exposition-textformats/src/main/java/io/prometheus/metrics/expositionformats/TextFormatUtil.java
+++ b/prometheus-metrics-exposition-textformats/src/main/java/io/prometheus/metrics/expositionformats/TextFormatUtil.java
@@ -67,7 +67,22 @@ public static MetricSnapshots mergeDuplicates(MetricSnapshots metricSnapshots) {
   }
 
   static void writeLong(Writer writer, long value) throws IOException {
-    writer.append(Long.toString(value));
+    if (value == Long.MIN_VALUE) {
+      writer.write("-9223372036854775808");
+      return;
+    }
+    char[] buf = new char[20];
+    int pos = 20;
+    boolean negative = value < 0;
+    long v = negative ? -value : value;
+    do {
+      buf[--pos] = (char) ('0' + (v % 10));
+      v /= 10;
+    } while (v > 0);
+    if (negative) {
+      buf[--pos] = '-';
+    }
+    writer.write(buf, pos, 20 - pos);
   }
 
   static void writeDouble(Writer writer, double d) throws IOException {
@@ -77,7 +92,6 @@ static void writeDouble(Writer writer, double d) throws IOException {
       writer.write("-Inf");
     } else {
       writer.write(Double.toString(d));
-      // FloatingDecimal.getBinaryToASCIIConverter(d).appendTo(writer);
     }
   }
 
@@ -86,7 +100,7 @@ static void writePrometheusTimestamp(Writer writer, long timestampMs, boolean ti
     if (timestampsInMs) {
       // correct for prometheus exposition format
       // https://prometheus.io/docs/instrumenting/exposition_formats/#text-format-details
-      writer.write(Long.toString(timestampMs));
+      writeLong(writer, timestampMs);
     } else {
       // incorrect for prometheus exposition format -
       // but we need to support it for backwards compatibility
@@ -95,7 +109,7 @@ static void writePrometheusTimestamp(Writer writer, long timestampMs, boolean ti
   }
 
   static void writeOpenMetricsTimestamp(Writer writer, long timestampMs) throws IOException {
-    writer.write(Long.toString(timestampMs / 1000L));
+    writeLong(writer, timestampMs / 1000L);
     writer.write(".");
     long ms = timestampMs % 1000;
     if (ms < 100) {
@@ -104,7 +118,7 @@ static void writeOpenMetricsTimestamp(Writer writer, long timestampMs) throws IO
     if (ms < 10) {
       writer.write("0");
     }
-    writer.write(Long.toString(ms));
+    writeLong(writer, ms);
   }
 
   static void writeEscapedString(Writer writer, String s) throws IOException {

From 5fe88b16c00fd64c5d482fccbbd7926cb8575a58 Mon Sep 17 00:00:00 2001
From: Jay DeLuca <jaydeluca4@gmail.com>
Date: Fri, 1 May 2026 16:37:04 -0400
Subject: [PATCH 4/6] fix lint

Signed-off-by: Jay DeLuca <jaydeluca4@gmail.com>
---
 .../metrics/benchmarks/HistogramTextFormatBenchmark.java  | 3 +--
 mise.toml                                                 | 1 +
 .../expositionformats/OpenMetricsTextFormatWriter.java    | 8 +-------
 .../expositionformats/PrometheusTextFormatWriter.java     | 8 +-------
 4 files changed, 4 insertions(+), 16 deletions(-)

diff --git a/benchmarks/src/main/java/io/prometheus/metrics/benchmarks/HistogramTextFormatBenchmark.java b/benchmarks/src/main/java/io/prometheus/metrics/benchmarks/HistogramTextFormatBenchmark.java
index 0ef1bbc2a..616e0c3e3 100644
--- a/benchmarks/src/main/java/io/prometheus/metrics/benchmarks/HistogramTextFormatBenchmark.java
+++ b/benchmarks/src/main/java/io/prometheus/metrics/benchmarks/HistogramTextFormatBenchmark.java
@@ -20,8 +20,7 @@
 import org.openjdk.jmh.annotations.State;
 
 /**
- * Benchmarks for writing a classic histogram (10 label combinations × 12 buckets) to text
- * formats.
+ * Benchmarks for writing a classic histogram (10 label combinations × 12 buckets) to text formats.
  *
  * <p>Two variants per format:
  *
diff --git a/mise.toml b/mise.toml
index cf5cb8657..803f0e09b 100644
--- a/mise.toml
+++ b/mise.toml
@@ -60,6 +60,7 @@ run = "./mvnw install -DskipTests -Dcoverage.skip=true"
 [tasks."lint"]
 description = "Run all lints"
 depends = ["lint:bom"]
+raw_args = true
 run = "flint run"
 
 [tasks."lint:fix"]
diff --git a/prometheus-metrics-exposition-textformats/src/main/java/io/prometheus/metrics/expositionformats/OpenMetricsTextFormatWriter.java b/prometheus-metrics-exposition-textformats/src/main/java/io/prometheus/metrics/expositionformats/OpenMetricsTextFormatWriter.java
index eeebad40c..83c98fde2 100644
--- a/prometheus-metrics-exposition-textformats/src/main/java/io/prometheus/metrics/expositionformats/OpenMetricsTextFormatWriter.java
+++ b/prometheus-metrics-exposition-textformats/src/main/java/io/prometheus/metrics/expositionformats/OpenMetricsTextFormatWriter.java
@@ -207,13 +207,7 @@ private void writeClassicHistogramBuckets(
       for (int i = 0; i < buckets.size(); i++) {
         cumulativeCount += buckets.getCount(i);
         writeNameAndLabels(
-            writer,
-            bucketName,
-            null,
-            data.getLabels(),
-            scheme,
-            "le",
-            buckets.getUpperBound(i));
+            writer, bucketName, null, data.getLabels(), scheme, "le", buckets.getUpperBound(i));
         writeLong(writer, cumulativeCount);
         Exemplar exemplar;
         if (i == 0) {
diff --git a/prometheus-metrics-exposition-textformats/src/main/java/io/prometheus/metrics/expositionformats/PrometheusTextFormatWriter.java b/prometheus-metrics-exposition-textformats/src/main/java/io/prometheus/metrics/expositionformats/PrometheusTextFormatWriter.java
index 2b68919c9..165992f25 100644
--- a/prometheus-metrics-exposition-textformats/src/main/java/io/prometheus/metrics/expositionformats/PrometheusTextFormatWriter.java
+++ b/prometheus-metrics-exposition-textformats/src/main/java/io/prometheus/metrics/expositionformats/PrometheusTextFormatWriter.java
@@ -220,13 +220,7 @@ private void writeHistogram(Writer writer, HistogramSnapshot snapshot, EscapingS
       for (int i = 0; i < buckets.size(); i++) {
         cumulativeCount += buckets.getCount(i);
         writeNameAndLabels(
-            writer,
-            bucketName,
-            null,
-            data.getLabels(),
-            scheme,
-            "le",
-            buckets.getUpperBound(i));
+            writer, bucketName, null, data.getLabels(), scheme, "le", buckets.getUpperBound(i));
         writeLong(writer, cumulativeCount);
         writeScrapeTimestampAndNewline(writer, data);
       }

From b29c0f14e0e2de64ad3f5e71a5ac4751e93dc562 Mon Sep 17 00:00:00 2001
From: Ubuntu <jaydeluca4@gmail.com>
Date: Sat, 2 May 2026 11:32:34 +0000
Subject: [PATCH 5/6] update benchmarks

Signed-off-by: Ubuntu <jaydeluca4@gmail.com>
---
 .../HistogramTextFormatBenchmark.java         | 60 +++++++++++++++++--
 mise.toml                                     | 10 ++++
 2 files changed, 64 insertions(+), 6 deletions(-)

diff --git a/benchmarks/src/main/java/io/prometheus/metrics/benchmarks/HistogramTextFormatBenchmark.java b/benchmarks/src/main/java/io/prometheus/metrics/benchmarks/HistogramTextFormatBenchmark.java
index 616e0c3e3..1699bc827 100644
--- a/benchmarks/src/main/java/io/prometheus/metrics/benchmarks/HistogramTextFormatBenchmark.java
+++ b/benchmarks/src/main/java/io/prometheus/metrics/benchmarks/HistogramTextFormatBenchmark.java
@@ -15,24 +15,43 @@
 import java.io.OutputStreamWriter;
 import java.io.Writer;
 import java.nio.charset.StandardCharsets;
+import java.util.concurrent.TimeUnit;
 import org.openjdk.jmh.annotations.Benchmark;
+import org.openjdk.jmh.annotations.Fork;
+import org.openjdk.jmh.annotations.Measurement;
 import org.openjdk.jmh.annotations.Scope;
 import org.openjdk.jmh.annotations.State;
+import org.openjdk.jmh.annotations.Warmup;
 
 /**
  * Benchmarks for writing a classic histogram (10 label combinations × 12 buckets) to text formats.
  *
- * <p>Two variants per format:
+ * <p>Three variants per format:
  *
  * <ul>
- *   <li>{@code writeToByteArray} — OutputStream path, new BufferedWriter created per call.
- *   <li>{@code reusingWriter} — Writer path, BufferedWriter reused across calls.
+ *   <li>{@code writeToByteArray} — OutputStream path, new BufferedWriter created per call (~41
+ *       KB/op; IO stack allocation dominates).
+ *   <li>{@code writeToNull} — OutputStream path to /dev/null, new BufferedWriter still created per
+ *       call (same allocation as writeToByteArray; shows ByteArrayOutputStream write cost is
+ *       negligible).
+ *   <li>{@code reusingWriter} — Writer path, BufferedWriter reused across calls (~18 KB/op; saves
+ *       the ~25 KB BufferedWriter char[] buffer and OutputStreamWriter per call).
+ *   <li>{@code reusingWriterToNull} — Writer path, BufferedWriter reused, output to /dev/null.
+ *       Lowest-allocation floor; isolates pure formatting CPU cost with zero IO stack overhead.
  * </ul>
  *
- * <p>Baseline (before allocation optimizations): ~41 KB/op for both Prometheus and OpenMetrics
- * formats, dominated by the per-call BufferedWriter buffer (~16 KB) and number-to-string
- * conversions.
+ * <p>Key allocation sources:
+ *
+ * <ul>
+ *   <li>BufferedWriter internal char[8192] buffer: 16,384 bytes per call (eliminated by reuse).
+ *   <li>OutputStreamWriter + StreamEncoder state: ~1–2 KB per call (eliminated by reuse).
+ *   <li>Remaining ~18 KB/op in reuse variants: ByteArrayOutputStream byte[] growth + any
+ *       per-call String allocations remaining in the format path.
+ * </ul>
  */
+@Fork(3)
+@Warmup(iterations = 5, time = 2, timeUnit = TimeUnit.SECONDS)
+@Measurement(iterations = 10, time = 2, timeUnit = TimeUnit.SECONDS)
 public class HistogramTextFormatBenchmark {
 
   private static final MetricSnapshots SNAPSHOTS;
@@ -95,6 +114,21 @@ public ReusableWriterState() {
     }
   }
 
+  @State(Scope.Benchmark)
+  public static class ReusableWriterToNullState {
+
+    final BufferedWriter openMetricsWriter;
+    final BufferedWriter prometheusWriter;
+
+    public ReusableWriterToNullState() {
+      OutputStream nullOutputStream = TextFormatUtilBenchmark.NullOutputStream.INSTANCE;
+      this.openMetricsWriter =
+          new BufferedWriter(new OutputStreamWriter(nullOutputStream, StandardCharsets.UTF_8));
+      this.prometheusWriter =
+          new BufferedWriter(new OutputStreamWriter(nullOutputStream, StandardCharsets.UTF_8));
+    }
+  }
+
   @Benchmark
   public OutputStream openMetricsWriteToByteArray(WriterState writerState) throws IOException {
     ByteArrayOutputStream byteArrayOutputStream = writerState.byteArrayOutputStream;
@@ -119,6 +153,13 @@ public Writer openMetricsReusingWriter(ReusableWriterState state) throws IOExcep
     return state.openMetricsWriter;
   }
 
+  @Benchmark
+  public Writer openMetricsReusingWriterToNull(ReusableWriterToNullState state) throws IOException {
+    OPEN_METRICS_TEXT_FORMAT_WRITER.write(
+        state.openMetricsWriter, SNAPSHOTS, EscapingScheme.ALLOW_UTF8);
+    return state.openMetricsWriter;
+  }
+
   @Benchmark
   public OutputStream prometheusWriteToByteArray(WriterState writerState) throws IOException {
     ByteArrayOutputStream byteArrayOutputStream = writerState.byteArrayOutputStream;
@@ -142,4 +183,11 @@ public Writer prometheusReusingWriter(ReusableWriterState state) throws IOExcept
         state.prometheusWriter, SNAPSHOTS, EscapingScheme.ALLOW_UTF8);
     return state.prometheusWriter;
   }
+
+  @Benchmark
+  public Writer prometheusReusingWriterToNull(ReusableWriterToNullState state) throws IOException {
+    PROMETHEUS_TEXT_FORMAT_WRITER.write(
+        state.prometheusWriter, SNAPSHOTS, EscapingScheme.ALLOW_UTF8);
+    return state.prometheusWriter;
+  }
 }
diff --git a/mise.toml b/mise.toml
index 803f0e09b..dac8930c4 100644
--- a/mise.toml
+++ b/mise.toml
@@ -110,6 +110,16 @@ echo "Running benchmarks with args: $JMH_ARGS"
 java -jar ./benchmarks/target/benchmarks.jar -rf json -rff benchmark-results.json $JMH_ARGS
 """
 
+[tasks."benchmark:format"]
+description = "Run format benchmarks only (HistogramTextFormat + TextFormatUtil), ~5 min"
+run = """
+./mvnw -pl benchmarks -am -DskipTests clean package -q
+java -jar ./benchmarks/target/benchmarks.jar \
+  "HistogramTextFormatBenchmark|TextFormatUtilBenchmark" \
+  -prof gc \
+  -rf json -rff format-benchmark-results.json
+"""
+
 [tasks."benchmark:generate-summary"]
 description = "Generate summary from existing benchmark-results.json"
 run = "python3 ./.mise/tasks/generate_benchmark_summary.py"

From b1f89baf39db0bedd2215c12f7535cf0f43dc75a Mon Sep 17 00:00:00 2001
From: Jay DeLuca <jaydeluca4@gmail.com>
Date: Sat, 2 May 2026 13:18:14 -0400
Subject: [PATCH 6/6] format

Signed-off-by: Jay DeLuca <jaydeluca4@gmail.com>
---
 .../benchmarks/HistogramTextFormatBenchmark.java       |  4 ++--
 mise.toml                                              | 10 ----------
 2 files changed, 2 insertions(+), 12 deletions(-)

diff --git a/benchmarks/src/main/java/io/prometheus/metrics/benchmarks/HistogramTextFormatBenchmark.java b/benchmarks/src/main/java/io/prometheus/metrics/benchmarks/HistogramTextFormatBenchmark.java
index 1699bc827..559f38638 100644
--- a/benchmarks/src/main/java/io/prometheus/metrics/benchmarks/HistogramTextFormatBenchmark.java
+++ b/benchmarks/src/main/java/io/prometheus/metrics/benchmarks/HistogramTextFormatBenchmark.java
@@ -45,8 +45,8 @@
  * <ul>
  *   <li>BufferedWriter internal char[8192] buffer: 16,384 bytes per call (eliminated by reuse).
  *   <li>OutputStreamWriter + StreamEncoder state: ~1–2 KB per call (eliminated by reuse).
- *   <li>Remaining ~18 KB/op in reuse variants: ByteArrayOutputStream byte[] growth + any
- *       per-call String allocations remaining in the format path.
+ *   <li>Remaining ~18 KB/op in reuse variants: ByteArrayOutputStream byte[] growth + any per-call
+ *       String allocations remaining in the format path.
  * </ul>
  */
 @Fork(3)
diff --git a/mise.toml b/mise.toml
index dac8930c4..803f0e09b 100644
--- a/mise.toml
+++ b/mise.toml
@@ -110,16 +110,6 @@ echo "Running benchmarks with args: $JMH_ARGS"
 java -jar ./benchmarks/target/benchmarks.jar -rf json -rff benchmark-results.json $JMH_ARGS
 """
 
-[tasks."benchmark:format"]
-description = "Run format benchmarks only (HistogramTextFormat + TextFormatUtil), ~5 min"
-run = """
-./mvnw -pl benchmarks -am -DskipTests clean package -q
-java -jar ./benchmarks/target/benchmarks.jar \
-  "HistogramTextFormatBenchmark|TextFormatUtilBenchmark" \
-  -prof gc \
-  -rf json -rff format-benchmark-results.json
-"""
-
 [tasks."benchmark:generate-summary"]
 description = "Generate summary from existing benchmark-results.json"
 run = "python3 ./.mise/tasks/generate_benchmark_summary.py"