From a0cb57fd7e7dfafd54070b5fdfbd4b4254ce6e95 Mon Sep 17 00:00:00 2001
From: Son Luong Ngoc <sluongng@gmail.com>
Date: Tue, 18 Apr 2023 14:28:40 +0200
Subject: [PATCH] [6.2.0] profile: add profile_finish_ts (#18129)

"date" field in Bazel json profile is a confusing field.

It uses Java Date.toString() output which includes local timezone
that could be hard to parse.

The name is misleading since users could mistook it for profile
start time, while it actually means the finish/end time, when
Bazel calls the writer to serialize profiling data to disk.

Add "profile_finish_ts" which has a clearer name and more consistent
value with the time unit being used in the rest of the JSON
profile(microseconds).

We shall deprecate the "date" field in a separate patch in a major
release.
---
 site/en/rules/performance.md                                 | 1 +
 .../com/google/devtools/build/lib/profiler/Profiler.java     | 5 ++++-
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/site/en/rules/performance.md b/site/en/rules/performance.md
index 0f80fdb6673f2f..a59fc0bfc27595 100644
--- a/site/en/rules/performance.md
+++ b/site/en/rules/performance.md
@@ -278,6 +278,7 @@ Example:
   "otherData": {
     "build_id": "101bff9a-7243-4c1a-8503-9dc6ae4c3b05",
     "date": "Tue Jun 16 08:30:21 CEST 2020",
+    "profile_finish_ts": "1677666095162000",
     "output_base": "/usr/local/google/_bazel_johndoe/573d4be77eaa72b91a3dfaa497bf8cd0"
   },
   "traceEvents": [
diff --git a/src/main/java/com/google/devtools/build/lib/profiler/Profiler.java b/src/main/java/com/google/devtools/build/lib/profiler/Profiler.java
index a99ed7e4bc93f2..913a46d08e215b 100644
--- a/src/main/java/com/google/devtools/build/lib/profiler/Profiler.java
+++ b/src/main/java/com/google/devtools/build/lib/profiler/Profiler.java
@@ -39,6 +39,7 @@
 import java.lang.management.ManagementFactory;
 import java.nio.charset.StandardCharsets;
 import java.time.Duration;
+import java.time.Instant;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Date;
@@ -1086,13 +1087,15 @@ public void run() {
                 // The buffer size of 262144 is chosen at random.
                 new OutputStreamWriter(
                     new BufferedOutputStream(outStream, 262144), StandardCharsets.UTF_8))) {
+          var finishDate = Instant.now();
           writer.beginObject();
           writer.name("otherData");
           writer.beginObject();
           writer.name("bazel_version").value(BlazeVersionInfo.instance().getReleaseName());
           writer.name("build_id").value(buildID.toString());
           writer.name("output_base").value(outputBase);
-          writer.name("date").value(new Date().toString());
+          writer.name("date").value(finishDate.toString());
+          writer.name("profile_finish_ts").value(finishDate.getEpochSecond() * 1000);
           writer.endObject();
           writer.name("traceEvents");
           writer.beginArray();