[https://nvbugs/6620324][fix] Judge perf-runner liveness on any output, not on newlines - #18220
[https://nvbugs/6620324][fix] Judge perf-runner liveness on any output, not on newlines#18220hyukn wants to merge 1 commit into
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…t, not on newlines The perf runner's stall detector kills a subprocess that produces no output for _STALL_TIMEOUT (1800s). Its reader thread used proc.stdout.readline(), so last_output_time only advanced when a full line arrived. That conflates two different things. A workload can be entirely healthy and still emit no newline for half an hour: - 84e05ec (NVIDIA#17596) set print_iter_log=False on the DeepSeek-R1-0528 FP4 ep8/ep4 bench cases to keep logs small, removing their only periodic newline-terminated output; - trtllm-bench's progress bar redraws with '\r' and never emits '\n', so readline() blocks straight through visible progress. Both R1 FP4 cases on B300 were running at 8-11 it/s when the detector SIGKILLed them at exactly 30 minutes, which surfaced as a bogus OOM/SIGKILL report. Read raw chunks with read1() instead and refresh last_output_time on any bytes received, then split records on \r as well as \n so progress redraws are preserved as separate lines for the fatal-pattern scan. A trailing fragment with no terminator is buffered and flushed at EOF, so output that never ends in a newline is still captured and still scanned. Signed-off-by: Yukun He <23156053+hyukn@users.noreply.github.com>
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Walkthrough
ChangesPerformance reader
Estimated code review effort: 2 (Simple) | ~10 minutes Merge Risk: 🟡 Moderate · up to A subprocess that emits a fatal error without a newline can remain monitored for up to 1800 seconds instead of being terminated after 180 seconds, delaying failure detection and wasting runner capacity; this should be fixed or explicitly accepted before merge. Suggested reviewers: 🚥 Pre-merge checks | ✅ 4 | ❌ 1❌ Failed checks (1 warning)
✅ Passed checks (4 passed)
Full details: Description checkExplanation The description clearly explains the issue, root cause, fix, preserved behavior, test coverage, and bug link. It omits the template's explicit PR Checklist section, but the required technical information is otherwise complete.
✨ Finishing Touches 💡 1🛠️ Fix failing CI checks 💡
🧪 Generate unit tests (beta)
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Inline comments:
In `@tests/integration/defs/perf/utils.py`:
- Around line 215-226: Update the nested _reader in
_run_command_with_captured_output to scan each raw chunk for _FATAL_PATTERNS
before decoding or waiting for a record terminator, maintaining a rolling byte
overlap so patterns split across chunks are detected; set has_error[0] while
holding lock when found, and add a regression test covering an unterminated
fatal pattern followed by a hang so the error stall timeout is selected.
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tests/integration/defs/perf/utils.py
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| pending += chunk | ||
| parts = re.split(rb'(?<=[\r\n])', pending) | ||
| # A trailing fragment without a terminator may still be growing. | ||
| pending = parts.pop() if not parts[-1].endswith((b'\n', b'\r')) else b'' |
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Pre-commit is red on this PR because yapf wants to rewrap this line and the next one — running pre-commit run --all-files locally will produce exactly this:
| pending = parts.pop() if not parts[-1].endswith((b'\n', b'\r')) else b'' | |
| pending = parts.pop() if not parts[-1].endswith( | |
| (b'\n', b'\r')) else b'' |
The decoded = [...] line right below needs the same treatment (yapf expands it into a bracketed list comprehension).
Required before merge, since Pre-commit Check is a blocking gate.
3 participants
Summary
The perf runner's stall detector kills a subprocess that produces no output for
_STALL_TIMEOUT(1800s). Its reader thread usedproc.stdout.readline(), solast_output_timeonly advanced when a full line arrived.That conflates "no output" with "no newline". A workload can be entirely healthy
and still emit no newline for half an hour:
84e05ecace([None][test] Adjust timeout test cases to avoid large log #17596) setprint_iter_log=Falseon the DeepSeek-R1-0528 FP4ep8/ep4 bench cases to keep logs small, removing their only periodic
newline-terminated output.
trtllm-bench's progress bar redraws with\rand never emits\n, soreadline()blocks straight through visible progress.Both R1 FP4 cases on B300 were running at 8-11 it/s when the detector
SIGKILLed them at exactly 30 minutes, which surfaced as a bogus OOM/SIGKILL
report (https://nvbugs/6620324).
Fix
Read raw chunks with
read1()and refreshlast_output_timeon any bytesreceived. Records are split on
\ras well as\n, so progress redraws arepreserved as separate lines for the
_FATAL_PATTERNSscan rather thanaccumulating into one huge line. A trailing fragment with no terminator is
buffered and flushed at EOF, so output that never ends in a newline is still
captured and still scanned.
Behaviour that does not change: the 1800s / 180s limits, the fatal-pattern
set, the kill path, and per-line output forwarded to Allure.
Test plan
Exercised the new reader against a real subprocess for five shapes:
\rprogress, no newlinesLinks
Dev Engineer Review
tests/integration/defs/perf/utils.pyto read subprocess output withread1().\rand\n.read1()behavior, decoding, EOF handling, and partial-record buffering across all supported subprocess streams.QA Engineer Review
tests/integration/defs/perf/utils.py.test-db/orqa/test-list coverage was added.