feat(tools): digest a performance trace for an issue or a pull request

tools/trace_digest.py reads an APS5_TRACE_FRAMES capture (aps5-trace-*.json.gz)
and prints a markdown report of a few KB, or the same data as JSON: the
summary line from aps5-summary.jsonl, the slowest frames with their largest
slices, the busy, wait and untraced time of each thread, the largest slices
per frame, the longest waits, and with --stacks the hottest frames of an
APS5_SAMPLE_WORKER collapsed-stack file. Python standard library only; a
unittest checks every section on a small synthetic trace.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
This commit is contained in:
AlxcBTW 2026-10-12 18:07:52 +02:00 committed by Adrià Franch
parent 2f4cc8983b
commit ca219d1b67
3 changed files with 353 additions and 0 deletions

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@ -97,6 +97,8 @@ if(BUILD_TESTING)
add_test(NAME pad_input COMMAND ${Python3_EXECUTABLE}
${CMAKE_CURRENT_SOURCE_DIR}/tools/tests/test_pad_input.py)
set_tests_properties(pad_input PROPERTIES TIMEOUT 20)
add_test(NAME trace_digest COMMAND ${Python3_EXECUTABLE}
${CMAKE_CURRENT_SOURCE_DIR}/tools/tests/test_trace_digest.py)
endif()
endif()

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@ -0,0 +1,129 @@
import contextlib
import gzip
import io
import json
import sys
import tempfile
import unittest
from pathlib import Path
sys.path.insert(0, str(Path(__file__).resolve().parents[1]))
import trace_digest
def complete(tid, name, ts, dur):
return {"name": name, "ph": "X", "ts": ts, "dur": dur, "pid": 7, "tid": tid}
EVENTS = [
{"name": "process_name", "ph": "M", "ts": 0, "pid": 7, "tid": 0, "args": {"name": "AnyPS5"}},
{"name": "thread_name", "ph": "M", "ts": 0, "pid": 7, "tid": 1, "args": {"name": "queue worker 0x0"}},
{"name": "thread_name", "ph": "M", "ts": 0, "pid": 7, "tid": 2, "args": {"name": "presenter"}},
complete(1, "Driver.WorkerWait", 0, 4000),
complete(1, "Driver.Packet", 4000, 5000),
complete(1, "Driver.Packet.memory_wait", 5000, 2000),
complete(1, "Driver.Packet", 12000, 16000),
complete(1, "Driver.Packet.draw", 13000, 7000),
complete(2, "Driver.Present", 0, 2000),
complete(2, "Driver.Present.inflight_wait", 500, 1000),
complete(2, "Driver.Present", 10000, 16000),
complete(2, "Driver.Present.inflight_wait", 10500, 14500),
{"name": "queue worker 0x0 folded", "ph": "C", "ts": 0, "pid": 7, "tid": 1, "args": {"ms": 1.5}},
{"name": "present", "ph": "i", "ts": 0, "pid": 7, "tid": 2, "s": "g", "args": {"present": 600}},
{"name": "present", "ph": "i", "ts": 10000, "pid": 7, "tid": 2, "s": "g", "args": {"present": 601}},
{"name": "present", "ph": "i", "ts": 30000, "pid": 7, "tid": 2, "s": "g", "args": {"present": 602}},
]
SUMMARY = {"commit": "abc", "dirty": False, "env": {"APS5_TRACE_FRAMES": "600:3"}, "gpu": "GPU", "driver": "Driver 1", "os": "OS 1",
"resolution": "1920x1080", "window": {"spec": "frames 600:3", "first_present": 600, "ms": 40.0}, "presents": 3,
"frame_ms": {"p50": 10.0, "p90": 20.0, "p99": 20.0, "max": 20.0}, "gpu_busy_ms_per_present": 5.0,
"worker_busy_pct": {"queue worker 0x0": 50.0}, "top_phases_ms_per_frame": {"Driver.Packet": 7.0}, "trace_dropped": False,
"trace": "aps5-trace-abc-7.json.gz"}
STACKS = "# samples=5 depth=64 truncated=1\n# module a.prx 0x1000 0x1\nntdll.dll+0x1;a.prx+0x10;a.prx+0x20 3\nntdll.dll+0x1;a.prx+0x10;a.prx+0x30 1\n[truncated];a.prx+0x40;a.prx+0x30 1\n"
class TraceDigestTests(unittest.TestCase):
def setUp(self):
self.directory = tempfile.TemporaryDirectory()
root = Path(self.directory.name)
self.trace = root / "aps5-trace-abc-7.json.gz"
with gzip.open(self.trace, "wt", encoding="utf-8") as handle:
json.dump({"traceEvents": EVENTS}, handle)
(root / "aps5-summary.jsonl").write_text(json.dumps(dict(SUMMARY, trace="other.json.gz")) + "\n" + json.dumps(SUMMARY) + "\n", encoding="utf-8")
self.stacks = root / "worker.collapsed.txt"
self.stacks.write_text(STACKS, encoding="utf-8")
def tearDown(self):
self.directory.cleanup()
def result(self):
return trace_digest.digest(trace_digest.load_trace(self.trace), trace_digest.load_summary(None, self.trace),
trace_digest.load_stacks(self.stacks), worst=2, top=3)
def test_summary_is_the_line_of_this_trace(self):
self.assertEqual(self.result()["summary"]["trace"], "aps5-trace-abc-7.json.gz")
def test_frames_end_at_the_window(self):
result = self.result()
self.assertEqual(result["frames"], 3)
self.assertAlmostEqual(result["window_ms"], 40.0)
def test_slowest_frame_lists_its_slices(self):
slowest = self.result()["slowest_frames"]
self.assertEqual([frame["present"] for frame in slowest], [601, 600])
self.assertAlmostEqual(slowest[0]["ms"], 20.0)
largest = {(entry["name"], entry["thread"]): entry["ms"] for entry in slowest[0]["slices"]}
self.assertAlmostEqual(largest[("Driver.Packet", "queue worker 0x0")], 16.0)
self.assertAlmostEqual(largest[("Driver.Present", "presenter")], 16.0)
self.assertAlmostEqual(largest[("Driver.Present.inflight_wait", "presenter")], 14.5)
def test_threads_split_busy_and_wait(self):
threads = {thread["thread"]: thread for thread in self.result()["threads"]}
worker = threads["queue worker 0x0"]
self.assertAlmostEqual(worker["wait_ms_per_frame"], 6.0 / 3)
self.assertAlmostEqual(worker["busy_ms_per_frame"], 19.0 / 3)
self.assertAlmostEqual(worker["untraced_ms_per_frame"], 15.0 / 3)
self.assertAlmostEqual(worker["folded_ms_per_frame"], 1.5 / 3)
self.assertEqual(worker["top"][0]["name"], "Driver.Packet")
presenter = threads["presenter"]
self.assertAlmostEqual(presenter["wait_ms_per_frame"], 15.5 / 3)
self.assertAlmostEqual(presenter["busy_ms_per_frame"], 2.5 / 3)
def test_largest_slices_per_frame(self):
largest = self.result()["top_slices_ms_per_frame"]
self.assertEqual(largest[0]["name"], "Driver.Packet")
self.assertAlmostEqual(largest[0]["ms"], 21.0 / 3)
def test_longest_waits(self):
waits = self.result()["longest_waits"]
self.assertEqual((waits[0]["name"], waits[0]["thread"], waits[0]["present"]), ("Driver.Present.inflight_wait", "presenter", 601))
self.assertAlmostEqual(waits[0]["ms"], 14.5)
self.assertEqual(waits[1]["name"], "Driver.WorkerWait")
def test_stacks_self_and_total(self):
stacks = self.result()["stacks"]
self.assertEqual(stacks["samples"], 5)
self.assertAlmostEqual(stacks["truncated_pct"], 20.0)
self.assertEqual(stacks["self"][0], {"frame": "a.prx+0x20", "pct": 60.0})
total = {entry["frame"]: entry["pct"] for entry in stacks["total"]}
self.assertEqual(stacks["common_frames"], 2)
self.assertNotIn("a.prx+0x10", total)
self.assertEqual(total, {"a.prx+0x20": 60.0, "a.prx+0x30": 40.0, "a.prx+0x40": 20.0})
def test_command_line_markdown_and_json(self):
output = io.StringIO()
with contextlib.redirect_stdout(output):
self.assertEqual(trace_digest.main([str(self.trace), "--stacks", str(self.stacks)]), 0)
text = output.getvalue()
for heading in ("**Slowest frames**", "**Threads**", "**Largest slices**", "**Longest waits**", "**Worker stacks**"):
self.assertIn(heading, text)
self.assertLess(len(text.encode("utf-8")), 5000)
output = io.StringIO()
with contextlib.redirect_stdout(output):
trace_digest.main([str(self.trace), "--json"])
self.assertEqual(json.loads(output.getvalue())["frames"], 3)
if __name__ == "__main__":
unittest.main()

222
tools/trace_digest.py Normal file
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import argparse
import bisect
import collections
import gzip
import json
import sys
from pathlib import Path
DESCRIPTION = """Digest of an APS5_TRACE_FRAMES / APS5_TRACE_SECONDS capture (aps5-trace-*.json.gz) for an issue or a
pull request: the summary line, the slowest frames with their largest slices, the busy and wait time of each
thread, the largest slices per frame, the longest waits and, with --stacks, the hottest functions of an
APS5_SAMPLE_WORKER collapsed-stack file. The summary line is read from aps5-summary.jsonl next to the trace
unless --summary names another file."""
def is_wait(name):
return "wait" in name.rsplit(".", 1)[-1].lower()
class Trace:
def __init__(self, document):
self.threads = {}
self.slices = collections.defaultdict(list)
self.presents = []
self.folded = collections.defaultdict(float)
for event in document["traceEvents"]:
phase = event.get("ph")
if phase == "M" and event.get("name") == "thread_name":
self.threads[event["tid"]] = event["args"]["name"]
elif phase == "X":
self.slices[event["tid"]].append([float(event["ts"]), float(event["dur"]), event["name"], 0, False])
elif phase == "i" and event.get("name") == "present":
self.presents.append((float(event["ts"]), event.get("args", {}).get("present")))
elif phase == "C":
self.folded[event["tid"]] += sum(float(value) for value in event.get("args", {}).values())
self.presents.sort()
for slices in self.slices.values():
slices.sort(key=lambda entry: (entry[0], -entry[1]))
stack = []
for entry in slices:
while stack and entry[0] >= stack[-1][0] + stack[-1][1]:
stack.pop()
entry[3] = len(stack)
entry[4] = any(is_wait(parent[2]) for parent in stack)
stack.append(entry)
def name(self, tid):
return self.threads.get(tid, f"tid {tid}")
def frames(self, end):
starts = [ts for ts, _ in self.presents]
if end is None:
end = starts[-1] if starts else 0.0
bounds = starts + ([end] if not starts or end > starts[-1] else [])
return [(index, bounds[index], bounds[index + 1], self.presents[index][1]) for index in range(len(bounds) - 1)]
def load_trace(path):
opener = gzip.open if str(path).endswith(".gz") else open
with opener(path, "rt", encoding="utf-8") as handle:
return Trace(json.load(handle))
def load_summary(path, trace_path):
candidate = Path(path) if path else Path(trace_path).with_name("aps5-summary.jsonl")
if not candidate.exists():
return None
lines = [json.loads(line) for line in candidate.read_text(encoding="utf-8").splitlines() if line.strip()]
for line in reversed(lines):
if path or line.get("trace") == Path(trace_path).name:
return line
return None
def load_stacks(path):
stacks = []
for line in Path(path).read_text(encoding="utf-8").splitlines():
if line.startswith("#") or not line.strip():
continue
frames, _, count = line.rpartition(" ")
stacks.append((frames.split(";"), int(count)))
return stacks
def digest(trace, summary=None, stacks=None, worst=5, top=10):
window_ms = summary["window"]["ms"] if summary else None
frames = trace.frames(window_ms * 1000.0 if window_ms is not None else None)
span_us = frames[-1][2] - frames[0][1] if frames else 0.0
count = max(len(frames), 1)
result = {"summary": summary, "frames": len(frames), "window_ms": span_us / 1000.0}
slowest = []
for index, begin, end, present in sorted(frames, key=lambda frame: frame[1] - frame[2])[:worst]:
inside = collections.Counter()
for tid, slices in trace.slices.items():
for ts, dur, name, _, _ in slices:
overlap = min(ts + dur, end) - max(ts, begin)
if overlap > 0:
inside[(name, trace.name(tid))] += overlap
slowest.append({"present": present, "ms": (end - begin) / 1000.0, "at_ms": begin / 1000.0,
"slices": [{"name": name, "thread": thread, "ms": us / 1000.0} for (name, thread), us in inside.most_common(4)]})
result["slowest_frames"] = slowest
threads = []
totals = collections.Counter()
waits = []
for tid, slices in sorted(trace.slices.items()):
traced = sum(dur for _, dur, _, depth, _ in slices if depth == 0)
waited = sum(dur for _, dur, name, _, nested in slices if is_wait(name) and not nested)
leaders = collections.Counter()
for ts, dur, name, depth, nested in slices:
totals[name] += dur
if depth == 0 and not is_wait(name):
leaders[name] += dur
if is_wait(name) and not nested:
waits.append((dur, name, trace.name(tid), ts))
threads.append({"thread": trace.name(tid), "busy_ms_per_frame": (traced - waited) / 1000.0 / count,
"wait_ms_per_frame": waited / 1000.0 / count,
"untraced_ms_per_frame": max(span_us - traced, 0.0) / 1000.0 / count,
"folded_ms_per_frame": trace.folded.get(tid, 0.0) / count,
"busy_pct": 100.0 * (traced - waited) / span_us if span_us else 0.0,
"wait_pct": 100.0 * waited / span_us if span_us else 0.0,
"top": [{"name": name, "ms_per_frame": us / 1000.0 / count} for name, us in leaders.most_common(2)]})
result["threads"] = threads
result["top_slices_ms_per_frame"] = [{"name": name, "ms": us / 1000.0 / count} for name, us in totals.most_common(top)]
starts = [ts for ts, _ in trace.presents]
result["longest_waits"] = [{"name": name, "thread": thread, "ms": dur / 1000.0, "at_ms": ts / 1000.0,
"present": trace.presents[bisect.bisect_right(starts, ts) - 1][1] if starts and ts >= starts[0] else None}
for dur, name, thread, ts in sorted(waits, reverse=True)[:top]]
if stacks is not None:
samples = sum(count for _, count in stacks)
own = collections.Counter()
inclusive = collections.Counter()
truncated = 0
common = None
for frames_of, number in stacks:
if frames_of[0] == "[truncated]":
truncated += number
frames_of = frames_of[1:]
elif frames_of:
common = set(frames_of) if common is None else common & set(frames_of)
if not frames_of:
continue
own[frames_of[-1]] += number
for frame in set(frames_of):
inclusive[frame] += number
common = common or set()
for frame in common:
del inclusive[frame]
share = lambda value: 100.0 * value / samples if samples else 0.0
result["stacks"] = {"samples": samples, "truncated_pct": share(truncated), "common_frames": len(common),
"self": [{"frame": frame, "pct": share(value)} for frame, value in own.most_common(top)],
"total": [{"frame": frame, "pct": share(value)} for frame, value in inclusive.most_common(top)]}
return result
def markdown(result):
lines = []
summary = result["summary"]
if summary:
frame = summary["frame_ms"]
lines.append(f"**{summary['window']['spec']}** from present {summary['window']['first_present']}: {summary['presents']} presents, "
f"frame p50 {frame['p50']:.1f} / p90 {frame['p90']:.1f} / p99 {frame['p99']:.1f} / max {frame['max']:.1f} ms, "
f"GPU busy {summary['gpu_busy_ms_per_present']:.1f} ms per present")
lines.append(f"{summary['gpu']}, {summary['driver']}, {summary['os']}, {summary['resolution']}, commit {summary['commit']}"
f"{' (dirty)' if summary.get('dirty') else ''}, dropped: {'yes' if summary['trace_dropped'] else 'no'}")
lines.append("")
lines.append("```json")
lines.append(json.dumps(summary, separators=(",", ":")))
lines.append("```")
else:
lines.append(f"{result['frames']} frames over {result['window_ms']:.1f} ms (no summary line found)")
lines.append("")
lines.append("**Slowest frames** (largest slices inside each, inclusive)")
lines.append("")
for frame in result["slowest_frames"]:
parts = ", ".join(f"{entry['name']} ({entry['thread']}) {entry['ms']:.1f}" for entry in frame["slices"])
lines.append(f"- present {frame['present']}: {frame['ms']:.1f} ms at {frame['at_ms']:.0f} ms: {parts}")
lines.append("")
lines.append("**Threads** (ms per frame)")
lines.append("")
lines.append("| thread | busy | wait | untraced | in slices < 20 us | largest |")
lines.append("|---|---|---|---|---|---|")
for thread in result["threads"]:
largest = ", ".join(f"{entry['name']} {entry['ms_per_frame']:.1f}" for entry in thread["top"])
lines.append(f"| {thread['thread']} | {thread['busy_ms_per_frame']:.1f} ({thread['busy_pct']:.0f} %) | {thread['wait_ms_per_frame']:.1f} ({thread['wait_pct']:.0f} %) "
f"| {thread['untraced_ms_per_frame']:.1f} | {thread['folded_ms_per_frame']:.1f} | {largest} |")
lines.append("")
lines.append("**Largest slices** (ms per frame, inclusive, all threads): " + ", ".join(f"{entry['name']} {entry['ms']:.1f}" for entry in result["top_slices_ms_per_frame"]))
lines.append("")
lines.append("**Longest waits**")
lines.append("")
for wait in result["longest_waits"]:
lines.append(f"- {wait['name']} ({wait['thread']}) {wait['ms']:.1f} ms at {wait['at_ms']:.0f} ms, present {wait['present']}")
if "stacks" in result:
stacks = result["stacks"]
lines.append("")
lines.append(f"**Worker stacks** ({stacks['samples']} samples, {stacks['truncated_pct']:.1f} % truncated; total leaves out the {stacks['common_frames']} frames every complete stack shares)")
lines.append("")
lines.append("- self: " + ", ".join(f"{entry['frame']} {entry['pct']:.1f} %" for entry in stacks["self"]))
lines.append("- total: " + ", ".join(f"{entry['frame']} {entry['pct']:.1f} %" for entry in stacks["total"]))
return "\n".join(lines) + "\n"
def main(arguments=None):
parser = argparse.ArgumentParser(description=DESCRIPTION)
parser.add_argument("trace", help="aps5-trace-*.json.gz (or .json)")
parser.add_argument("--summary", help="file with the summary line (default: aps5-summary.jsonl next to the trace)")
parser.add_argument("--stacks", help="collapsed-stack file of APS5_SAMPLE_WORKER (<file stem>.collapsed.txt)")
parser.add_argument("--frames", type=int, default=5, help="slowest frames to list (default 5)")
parser.add_argument("--top", type=int, default=10, help="entries per list (default 10)")
parser.add_argument("--json", action="store_true", help="print the digest as JSON")
options = parser.parse_args(arguments)
result = digest(load_trace(options.trace), load_summary(options.summary, options.trace),
load_stacks(options.stacks) if options.stacks else None, options.frames, options.top)
sys.stdout.write(json.dumps(result, indent=1) + "\n" if options.json else markdown(result))
return 0
if __name__ == "__main__":
sys.exit(main())