git: fca5cfd584d8 - main - lockprof: retire lock_prof_skipcount

[Mateusz Guzik]

The branch main has been updated by mjg:

URL: https://cgit.FreeBSD.org/src/commit/?id=fca5cfd584d81ca291dbd898a8ff60c52d8c3c42

commit fca5cfd584d81ca291dbd898a8ff60c52d8c3c42
Author:     Mateusz Guzik <mjg at FreeBSD.org>
AuthorDate: 2021-05-18 19:05:42 +0000
Commit:     Mateusz Guzik <mjg at FreeBSD.org>
CommitDate: 2021-05-22 19:28:37 +0000

    lockprof: retire lock_prof_skipcount
    
    The implementation uses a global variable for *ALL* calls, defeating the
    point of sampling in the first place. Remove it as it clearly remains
    unused.
---
 sys/kern/subr_lock.c | 7 -------
 1 file changed, 7 deletions(-)

diff --git a/sys/kern/subr_lock.c b/sys/kern/subr_lock.c
index 1afaa19302ed..97b880b54ea2 100644
--- a/sys/kern/subr_lock.c
+++ b/sys/kern/subr_lock.c
@@ -278,7 +278,6 @@ static volatile int lock_prof_resetting;
 
 static int lock_prof_rejected;
 static int lock_prof_skipspin;
-static int lock_prof_skipcount;
 
 #ifndef USE_CPU_NANOSECONDS
 uint64_t
@@ -597,7 +596,6 @@ void
 lock_profile_obtain_lock_success(struct lock_object *lo, int contested,
     uint64_t waittime, const char *file, int line)
 {
-	static int lock_prof_count;
 	struct lock_profile_object *l;
 	int spin;
 
@@ -607,9 +605,6 @@ 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_prof_skipcount &&
-	    (++lock_prof_count % lock_prof_skipcount) != 0)
-		return;
 	spin = (LOCK_CLASS(lo)->lc_flags & LC_SPINLOCK) ? 1 : 0;
 	if (spin && lock_prof_skipspin == 1)
 		return;
@@ -732,8 +727,6 @@ static SYSCTL_NODE(_debug_lock, OID_AUTO, prof,
     "lock profiling");
 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, skipcount, CTLFLAG_RW,
-    &lock_prof_skipcount, 0, "Sample approximately every N lock acquisitions.");
 SYSCTL_INT(_debug_lock_prof, OID_AUTO, rejected, CTLFLAG_RD,
     &lock_prof_rejected, 0, "Number of rejected profiling records");
 SYSCTL_PROC(_debug_lock_prof, OID_AUTO, stats,