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Instead of get_cyclecount(9), use nanotime(9) to record acquisition and

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release times.  Measurements are made and stored in nanoseconds but
presented in microseconds, which should be sufficient for the locks for
which we actually want this (those that are held long and / or often).
Also, rename some variables and structure members to unit-agnostic names.
This commit is contained in:
Dag-Erling Smørgrav 2002-04-02 14:42:01 +00:00
parent 920153807b
commit b784ffe91a
3 changed files with 57 additions and 39 deletions
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47
sys/kern/kern_mutex.c
View File

@ -212,7 +212,7 @@ struct mutex_prof {
#define MPROF_TOT 1 #define MPROF_TOT 1
#define MPROF_CNT 2 #define MPROF_CNT 2
#define MPROF_AVG 3 #define MPROF_AVG 3
u_int64_t cycles[4]; u_int64_t counter[4];
}; };
/* /*
@ -258,6 +258,15 @@ mprof_init(void *arg __unused)
} }
SYSINIT(mprofinit, SI_SUB_LOCK, SI_ORDER_ANY, mprof_init, NULL); SYSINIT(mprofinit, SI_SUB_LOCK, SI_ORDER_ANY, mprof_init, NULL);
static u_int64_t
nanoseconds(void)
{
struct timespec tv;
nanotime(&tv);
return (tv.tv_sec * (u_int64_t)1000000000 + tv.tv_nsec);
}
static int static int
dump_mutex_prof_stats(SYSCTL_HANDLER_ARGS) dump_mutex_prof_stats(SYSCTL_HANDLER_ARGS)
{ {
@ -274,10 +283,10 @@ dump_mutex_prof_stats(SYSCTL_HANDLER_ARGS)
mtx_lock_spin(&mprof_mtx); mtx_lock_spin(&mprof_mtx);
for (i = 0; i < first_free_mprof_buf; ++i) for (i = 0; i < first_free_mprof_buf; ++i)
sbuf_printf(sb, "%12llu %12llu %12llu %12llu %s:%d (%s)\n", sbuf_printf(sb, "%12llu %12llu %12llu %12llu %s:%d (%s)\n",
mprof_buf[i].cycles[MPROF_MAX], mprof_buf[i].counter[MPROF_MAX] / 1000,
mprof_buf[i].cycles[MPROF_TOT], mprof_buf[i].counter[MPROF_TOT] / 1000,
mprof_buf[i].cycles[MPROF_CNT], mprof_buf[i].counter[MPROF_CNT],
mprof_buf[i].cycles[MPROF_AVG], mprof_buf[i].counter[MPROF_AVG] / 1000,
mprof_buf[i].file, mprof_buf[i].line, mprof_buf[i].name); mprof_buf[i].file, mprof_buf[i].line, mprof_buf[i].name);
mtx_unlock_spin(&mprof_mtx); mtx_unlock_spin(&mprof_mtx);
sbuf_finish(sb); sbuf_finish(sb);
@ -304,10 +313,10 @@ _mtx_lock_flags(struct mtx *m, int opts, const char *file, int line)
WITNESS_LOCK(&m->mtx_object, opts | LOP_EXCLUSIVE, file, line); WITNESS_LOCK(&m->mtx_object, opts | LOP_EXCLUSIVE, file, line);
#ifdef MUTEX_PROFILING #ifdef MUTEX_PROFILING
/* don't reset the timer when/if recursing */ /* don't reset the timer when/if recursing */
if (m->cycles == 0) { if (m->acqtime == 0) {
m->file = file; m->file = file;
m->line = line; m->line = line;
m->cycles = mutex_prof_enable ? get_cyclecount() : 0; m->acqtime = mutex_prof_enable ? nanoseconds() : 0;
++mutex_prof_acquisitions; ++mutex_prof_acquisitions;
} }
#endif #endif
@ -320,17 +329,17 @@ _mtx_unlock_flags(struct mtx *m, int opts, const char *file, int line)
MPASS(curthread != NULL); MPASS(curthread != NULL);
mtx_assert(m, MA_OWNED); mtx_assert(m, MA_OWNED);
#ifdef MUTEX_PROFILING #ifdef MUTEX_PROFILING
if (m->cycles != 0) { if (m->acqtime != 0) {
static const char *unknown = "(unknown)"; static const char *unknown = "(unknown)";
struct mutex_prof *mpp; struct mutex_prof *mpp;
u_int64_t cycles, mcycles; u_int64_t acqtime, now;
const char *p, *q; const char *p, *q;
volatile u_int hash, n; volatile u_int hash, n;
cycles = get_cyclecount(); now = nanoseconds();
mcycles = m->cycles; acqtime = m->acqtime;
m->cycles = 0; m->acqtime = 0;
if (cycles <= mcycles) if (now <= acqtime)
goto out; goto out;
for (p = file; strncmp(p, "../", 3) == 0; p += 3) for (p = file; strncmp(p, "../", 3) == 0; p += 3)
/* nothing */ ; /* nothing */ ;
@ -363,12 +372,12 @@ _mtx_unlock_flags(struct mtx *m, int opts, const char *file, int line)
* Record if the mutex has been held longer now than ever * Record if the mutex has been held longer now than ever
* before * before
*/ */
if ((cycles - mcycles) > mpp->cycles[MPROF_MAX]) if ((now - acqtime) > mpp->counter[MPROF_MAX])
mpp->cycles[MPROF_MAX] = cycles - mcycles; mpp->counter[MPROF_MAX] = now - acqtime;
mpp->cycles[MPROF_TOT] += cycles - mcycles; mpp->counter[MPROF_TOT] += now - acqtime;
mpp->cycles[MPROF_CNT] += 1; mpp->counter[MPROF_CNT] += 1;
mpp->cycles[MPROF_AVG] = mpp->counter[MPROF_AVG] =
mpp->cycles[MPROF_TOT] / mpp->cycles[MPROF_CNT]; mpp->counter[MPROF_TOT] / mpp->counter[MPROF_CNT];
unlock: unlock:
mtx_unlock_spin(&mprof_mtx); mtx_unlock_spin(&mprof_mtx);
} }

47
sys/kern/subr_turnstile.c
View File

@ -212,7 +212,7 @@ struct mutex_prof {
#define MPROF_TOT 1 #define MPROF_TOT 1
#define MPROF_CNT 2 #define MPROF_CNT 2
#define MPROF_AVG 3 #define MPROF_AVG 3
u_int64_t cycles[4]; u_int64_t counter[4];
}; };
/* /*
@ -258,6 +258,15 @@ mprof_init(void *arg __unused)
} }
SYSINIT(mprofinit, SI_SUB_LOCK, SI_ORDER_ANY, mprof_init, NULL); SYSINIT(mprofinit, SI_SUB_LOCK, SI_ORDER_ANY, mprof_init, NULL);
static u_int64_t
nanoseconds(void)
{
struct timespec tv;
nanotime(&tv);
return (tv.tv_sec * (u_int64_t)1000000000 + tv.tv_nsec);
}
static int static int
dump_mutex_prof_stats(SYSCTL_HANDLER_ARGS) dump_mutex_prof_stats(SYSCTL_HANDLER_ARGS)
{ {
@ -274,10 +283,10 @@ dump_mutex_prof_stats(SYSCTL_HANDLER_ARGS)
mtx_lock_spin(&mprof_mtx); mtx_lock_spin(&mprof_mtx);
for (i = 0; i < first_free_mprof_buf; ++i) for (i = 0; i < first_free_mprof_buf; ++i)
sbuf_printf(sb, "%12llu %12llu %12llu %12llu %s:%d (%s)\n", sbuf_printf(sb, "%12llu %12llu %12llu %12llu %s:%d (%s)\n",
mprof_buf[i].cycles[MPROF_MAX], mprof_buf[i].counter[MPROF_MAX] / 1000,
mprof_buf[i].cycles[MPROF_TOT], mprof_buf[i].counter[MPROF_TOT] / 1000,
mprof_buf[i].cycles[MPROF_CNT], mprof_buf[i].counter[MPROF_CNT],
mprof_buf[i].cycles[MPROF_AVG], mprof_buf[i].counter[MPROF_AVG] / 1000,
mprof_buf[i].file, mprof_buf[i].line, mprof_buf[i].name); mprof_buf[i].file, mprof_buf[i].line, mprof_buf[i].name);
mtx_unlock_spin(&mprof_mtx); mtx_unlock_spin(&mprof_mtx);
sbuf_finish(sb); sbuf_finish(sb);
@ -304,10 +313,10 @@ _mtx_lock_flags(struct mtx *m, int opts, const char *file, int line)
WITNESS_LOCK(&m->mtx_object, opts | LOP_EXCLUSIVE, file, line); WITNESS_LOCK(&m->mtx_object, opts | LOP_EXCLUSIVE, file, line);
#ifdef MUTEX_PROFILING #ifdef MUTEX_PROFILING
/* don't reset the timer when/if recursing */ /* don't reset the timer when/if recursing */
if (m->cycles == 0) { if (m->acqtime == 0) {
m->file = file; m->file = file;
m->line = line; m->line = line;
m->cycles = mutex_prof_enable ? get_cyclecount() : 0; m->acqtime = mutex_prof_enable ? nanoseconds() : 0;
++mutex_prof_acquisitions; ++mutex_prof_acquisitions;
} }
#endif #endif
@ -320,17 +329,17 @@ _mtx_unlock_flags(struct mtx *m, int opts, const char *file, int line)
MPASS(curthread != NULL); MPASS(curthread != NULL);
mtx_assert(m, MA_OWNED); mtx_assert(m, MA_OWNED);
#ifdef MUTEX_PROFILING #ifdef MUTEX_PROFILING
if (m->cycles != 0) { if (m->acqtime != 0) {
static const char *unknown = "(unknown)"; static const char *unknown = "(unknown)";
struct mutex_prof *mpp; struct mutex_prof *mpp;
u_int64_t cycles, mcycles; u_int64_t acqtime, now;
const char *p, *q; const char *p, *q;
volatile u_int hash, n; volatile u_int hash, n;
cycles = get_cyclecount(); now = nanoseconds();
mcycles = m->cycles; acqtime = m->acqtime;
m->cycles = 0; m->acqtime = 0;
if (cycles <= mcycles) if (now <= acqtime)
goto out; goto out;
for (p = file; strncmp(p, "../", 3) == 0; p += 3) for (p = file; strncmp(p, "../", 3) == 0; p += 3)
/* nothing */ ; /* nothing */ ;
@ -363,12 +372,12 @@ _mtx_unlock_flags(struct mtx *m, int opts, const char *file, int line)
* Record if the mutex has been held longer now than ever * Record if the mutex has been held longer now than ever
* before * before
*/ */
if ((cycles - mcycles) > mpp->cycles[MPROF_MAX]) if ((now - acqtime) > mpp->counter[MPROF_MAX])
mpp->cycles[MPROF_MAX] = cycles - mcycles; mpp->counter[MPROF_MAX] = now - acqtime;
mpp->cycles[MPROF_TOT] += cycles - mcycles; mpp->counter[MPROF_TOT] += now - acqtime;
mpp->cycles[MPROF_CNT] += 1; mpp->counter[MPROF_CNT] += 1;
mpp->cycles[MPROF_AVG] = mpp->counter[MPROF_AVG] =
mpp->cycles[MPROF_TOT] / mpp->cycles[MPROF_CNT]; mpp->counter[MPROF_TOT] / mpp->counter[MPROF_CNT];
unlock: unlock:
mtx_unlock_spin(&mprof_mtx); mtx_unlock_spin(&mprof_mtx);
} }

2
sys/sys/_mutex.h
View File

@ -42,7 +42,7 @@ struct mtx {
TAILQ_HEAD(, thread) mtx_blocked; /* threads blocked on this lock */ TAILQ_HEAD(, thread) mtx_blocked; /* threads blocked on this lock */
LIST_ENTRY(mtx) mtx_contested; /* list of all contested locks */ LIST_ENTRY(mtx) mtx_contested; /* list of all contested locks */
/* #ifdef MUTEX_PROFILING */ /* #ifdef MUTEX_PROFILING */
u_int64_t cycles; u_int64_t acqtime;
const char *file; const char *file;
int line; int line;
/* #endif */ /* #endif */