A new thread starts in fork_exit(), not mi_switch(), so its PMCs are
not loaded until its next context switch. Call the switch-in hook
there.
Depends on D60564
Details
Details
- Reviewers
mhorne gnn ali_mashtizadeh.com kib markj ojanerif_amd.com - Group Reviewers
pmc - Commits
- rG1bb8b1d99a6c: hwpmc: switch in process PMCs on a thread's first run
Summary
Test Plan
Built amd64 GENERIC + hwpmc.ko, GENERIC without HWPMC_HOOKS, and arm64.
Ran tests/sys/pmc on AMD Zen 6 (LBR v2).
Diff Detail
Diff Detail
- Repository
- rG FreeBSD src repository
- Lint
Lint Skipped - Unit
Tests Skipped - Build Status
Buildable 78196 Build 75079: arc lint + arc unit
Event Timeline
Herald added subscribers: olce, imp. · View Herald TranscriptOct 10 2026, 1:22 AM2026-10-10 01:22:40 (UTC+0)
afscoelho_gmail.com requested review of this revision.Oct 10 2026, 1:22 AM2026-10-10 01:22:40 (UTC+0)
Harbormaster completed remote builds in B77938: Diff 189320.Oct 10 2026, 1:22 AM2026-10-10 01:22:40 (UTC+0)
This revision is now accepted and ready to land.Oct 10 2026, 9:29 AM2026-10-10 09:29:22 (UTC+0)
afscoelho_gmail.com updated this revision to Diff 189844.Oct 14 2026, 12:44 AM2026-10-14 00:44:03 (UTC+0)
Comment ActionsRebase only. No code change.
This revision now requires review to proceed.Oct 14 2026, 12:44 AM2026-10-14 00:44:03 (UTC+0)
Harbormaster completed remote builds in B78196: Diff 189844.Oct 14 2026, 12:44 AM2026-10-14 00:44:03 (UTC+0)
Comment Actions
Rebase-only update to add the Differential Revision trailer; no code change.
@kib, could you please re-accept?
This revision is now accepted and ready to land.Oct 14 2026, 2:23 AM2026-10-14 02:23:43 (UTC+0)
Closed by commit rG1bb8b1d99a6c: hwpmc: switch in process PMCs on a thread's first run. · Explain WhyFri, Nov 13, 2:32 PM2026-11-13 14:32:37 (UTC+0)
This revision was automatically updated to reflect the committed changes.
afscoelho_gmail.com mentioned this in D59359: hwpmc: multiplex system-mode groups per CPU.Fri, Nov 13, 5:09 PM2026-11-13 17:09:42 (UTC+0)
afscoelho_gmail.com mentioned this in D57633: hwpmc: PMC group syscalls, attach hook, and process-exit drain.
afscoelho_gmail.com mentioned this in D57636: libpmcstat: parse {a,b,c} brace-list event group syntax.
afscoelho_gmail.com mentioned this in D57637: pmcstat(8): add -b batch-grouping flag and scale multiplexed counts.
afscoelho_gmail.com mentioned this in D59363: pmcstat(8): warn about unfittable grouped sample periods.
afscoelho_gmail.com mentioned this in D57640: tools/regression/pmc: hwpmc multiplex positive-path test.
afscoelho_gmail.com mentioned this in D57641: tools/regression/pmc: libpmcstat group-parser unit test.
afscoelho_gmail.com mentioned this in D59366: tools/regression/pmc: test multiplex drain and rotation.