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| author | Mateusz Guzik <mjg@FreeBSD.org> | 2021-05-18 19:07:19 +0000 |
|---|---|---|
| committer | Mateusz Guzik <mjg@FreeBSD.org> | 2021-06-02 15:00:22 +0000 |
| commit | f03b2f7c8b814ad5c71c519316644541dd5ceae2 (patch) | |
| tree | fb2e22eb504e0bcaecf932c7353df6e608a677c1 | |
| parent | 3b78559094fea6320b925966a05cc14416b71c4a (diff) | |
| download | src-f03b2f7c8b814ad5c71c519316644541dd5ceae2.tar.gz src-f03b2f7c8b814ad5c71c519316644541dd5ceae2.zip | |
lockprof: add contested-only profiling
This allows tracking all wait times with much smaller runtime impact.
For example when doing -j 104 buildkernel on tmpfs:
no profiling: 2921.70s user 282.72s system 6598% cpu 48.562 total
all acquires: 2926.87s user 350.53s system 6656% cpu 49.237 total
contested only: 2919.64s user 290.31s system 6583% cpu 48.756 total
(cherry picked from commit a0842e69aa5f86d61c072544b540ef21b2015211)
| -rw-r--r-- | sys/kern/subr_lock.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/sys/kern/subr_lock.c b/sys/kern/subr_lock.c index 09113836efe5..6d91118ae0f3 100644 --- a/sys/kern/subr_lock.c +++ b/sys/kern/subr_lock.c @@ -271,6 +271,7 @@ DPCPU_DEFINE_STATIC(struct lock_prof_cpu, lp); #define LP_CPU(cpu) (DPCPU_ID_PTR((cpu), lp)) volatile int __read_mostly lock_prof_enable; +int __read_mostly lock_contested_only; static volatile int lock_prof_resetting; #define LPROF_SBUF_SIZE 256 @@ -604,6 +605,8 @@ lock_profile_obtain_lock_success(struct lock_object *lo, int contested, /* don't reset the timer when/if recursing */ if (!lock_prof_enable || (lo->lo_flags & LO_NOPROFILE)) return; + if (lock_contested_only && !contested) + return; spin = (LOCK_CLASS(lo)->lc_flags & LC_SPINLOCK) ? 1 : 0; if (spin && lock_prof_skipspin == 1) return; @@ -728,6 +731,8 @@ SYSCTL_INT(_debug_lock_prof, OID_AUTO, skipspin, CTLFLAG_RW, &lock_prof_skipspin, 0, "Skip profiling on spinlocks."); SYSCTL_INT(_debug_lock_prof, OID_AUTO, rejected, CTLFLAG_RD, &lock_prof_rejected, 0, "Number of rejected profiling records"); +SYSCTL_INT(_debug_lock_prof, OID_AUTO, contested_only, CTLFLAG_RW, + &lock_contested_only, 0, "Only profile contested acquires"); SYSCTL_PROC(_debug_lock_prof, OID_AUTO, stats, CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 0, dump_lock_prof_stats, "A", |