For shape-heavy ops the autotune sweep dominates wall time, not the
measurement. _parallel_warmup_plugin shards the sweep across N GPUs and
hands the merged configs to the normal single-GPU serial measurement, so
timing stays comparable. Activated by PARALLEL_WARMUP_GPUS=N (silent
no-op when unset, so it can stay in the plugin list); output layout,
REPLAY_FROM usage and the latency table are unchanged.
Measurement is deliberately not parallelized: N processes saturating one
box couple through the power/thermal budget, so per-card latency gets
dragged by its neighbours by an amount that does not reproduce. Config
keys whose winner differs across shards are counted and reported as a
WARNING -- that count is how much to trust the run.
Fixes found while auditing:
- Shards no longer overwrite CUDA_VISIBLE_DEVICES with a bare shard
index, which a caller who had selected idle cards (e.g. 6,7) would see
re-interpreted as absolute ids 0,1 -- silently benchmarking on the busy
cards they were avoiding.
- Interrupting the sweep no longer leaves N subprocesses holding GPUs;
children are terminated and reaped before the exception propagates
(BaseException, since KeyboardInterrupt is not an Exception).
- run_pytest.sh claims its output dir with a bare mkdir and retreats to
a -2/-3 suffix on collision. The second-resolution timestamp meant two
concurrent runs shared one directory and overwrote each other.
- Replay eviction failures now emit a distinct compile_*_no_evict marker.
LibTuner.cache is a sqlite-backed ConfigCache with no __delitem__, so
the bad config could not be dropped and the retry re-read it, while the
log still claimed a clean fallback to live autotune.
Also trims comment density in both shell scripts and reworks the README:
promotes the parallel and cudagraph sections out from under the A/B flow,
groups the env table by purpose, documents that two record-mode runs are
not comparable, and marks ab_fold_test.sh as a caliber example whose
switch upstream has already removed.
LibTuner.cache is a view onto flag_gems' persistent sqlite config DB
(~/.flaggems/config_cache/TunedConfig_*.db), which survives across runs.
Both record and replay assumed a cold, in-process cache:
- record captured the chosen config by diffing cache keys before/after
run(). On a warm DB the key is already present, LibTuner.run takes the
cached branch without writing it again, so the diff was always empty
and nothing was recorded for any libtuner kernel. Only @triton.autotune
kernels (in-process cache) made it into the json -- e.g. a
fused_marlin_moe_mxfp4 run recorded moe_sum_kernel alone, missing both
MXFP4 GEMMs.
- replay only injected when the key was absent from the cache, so a warm
DB skipped injection entirely: the run reported "replaying N entries"
while actually self-tuning.
Record now reads back this call's own self.cache[key] after run();
replay overwrites unconditionally. Verified on fused_marlin_moe_mxfp4:
recorded entries 1 -> 6 (both GEMMs present), replay injects all 6 with
zero AUTOTUNE_REPLAY_FALLBACK and reproduces latency.
README: note that "fresh tune per side" requires dropping the sqlite DB
(not merely omitting REPLAY_FROM), and how to verify record coverage.
Plain autotune is the common case (fast, same-config A/B); FlagTune's
exhaustive first-run search is now opt-in via USE_FLAGTUNE=1.
ab_fold_test.sh automates the FLAGGEMS_MXFP4_FOLDSCALE=0/1 record-replay
comparison over the four DeepSeek-V4-Flash trace shape sets, which are
now tracked under runs/shape/.
- _cudagraph_plugin: warm up autotune/JIT explicitly before graph capture
(internal 5-iter warmup is too short), tag fallback markers with the
failing phase; first-run latency no longer jitters run-to-run.
- _device_guard_plugin (new): set GEMS_VENDOR via torch probe before
importing flag_gems, avoiding its timeout-less nvidia-smi subprocess
probe that can hang import in fork-broken environments.
- _pretty_report_plugin (new) + _term_style (new): fold inputs identical
across all result rows into a legend line, color status/plugin
tags/markers on the live terminal; run.log is ANSI-stripped and keeps
upstream SUCCESS/column wording for grep compatibility.
- run_pytest.sh: make USE_FLAGTUNE overridable, group all knobs into a
config section with Chinese comments, add start/end banners.
- README: document the warmup semantics, new plugins/env vars, and the
A/B rule that both sides must use the same USE_FLAGTUNE.
zhoulin