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Revert to open hashing. It makes the code simpler, and works farily well

Browse Source 
even when the number of records approaches the size of the hash table.
Besides, the previous implementation (using linear probing) was broken :)

Also, use the newly introduced MTX_SYSINIT.
This commit is contained in:
des 2002-04-02 23:26:32 +00:00
parent a06ed407a7
commit 2a92b78602
2 changed files with 20 additions and 32 deletions
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26
sys/kern/kern_mutex.c
View File

@ -219,6 +219,7 @@ struct mutex_prof {
#define MPROF_CNT 2 #define MPROF_CNT 2
#define MPROF_AVG 3 #define MPROF_AVG 3
u_int64_t counter[4]; u_int64_t counter[4];
struct mutex_prof *next;
}; };
/* /*
@ -227,10 +228,10 @@ struct mutex_prof {
* *
* Note: NUM_MPROF_BUFFERS must be smaller than MPROF_HASH_SIZE. * Note: NUM_MPROF_BUFFERS must be smaller than MPROF_HASH_SIZE.
*/ */
#define NUM_MPROF_BUFFERS 4096 #define NUM_MPROF_BUFFERS 1000
static struct mutex_prof mprof_buf[NUM_MPROF_BUFFERS]; static struct mutex_prof mprof_buf[NUM_MPROF_BUFFERS];
static int first_free_mprof_buf; static int first_free_mprof_buf;
#define MPROF_HASH_SIZE 32771 #define MPROF_HASH_SIZE 1009
static struct mutex_prof *mprof_hash[MPROF_HASH_SIZE]; static struct mutex_prof *mprof_hash[MPROF_HASH_SIZE];
static int mutex_prof_acquisitions; static int mutex_prof_acquisitions;
@ -256,13 +257,7 @@ SYSCTL_INT(_debug_mutex_prof, OID_AUTO, collisions, CTLFLAG_RD,
* mprof_mtx protects the profiling buffers and the hash. * mprof_mtx protects the profiling buffers and the hash.
*/ */
static struct mtx mprof_mtx; static struct mtx mprof_mtx;
MTX_SYSINIT(mprof, &mprof_mtx, "mutex profiling lock", MTX_SPIN | MTX_QUIET);
static void
mprof_init(void *arg __unused)
{
mtx_init(&mprof_mtx, "mutex profiling lock", MTX_SPIN | MTX_QUIET);
}
SYSINIT(mprofinit, SI_SUB_LOCK, SI_ORDER_ANY, mprof_init, NULL);
static u_int64_t static u_int64_t
nanoseconds(void) nanoseconds(void)
@ -340,7 +335,7 @@ _mtx_unlock_flags(struct mtx *m, int opts, const char *file, int line)
struct mutex_prof *mpp; struct mutex_prof *mpp;
u_int64_t acqtime, now; u_int64_t acqtime, now;
const char *p, *q; const char *p, *q;
volatile u_int hash, n; volatile u_int hash;
now = nanoseconds(); now = nanoseconds();
acqtime = m->acqtime; acqtime = m->acqtime;
@ -354,12 +349,9 @@ _mtx_unlock_flags(struct mtx *m, int opts, const char *file, int line)
for (hash = line, q = p; *q != '\0'; ++q) for (hash = line, q = p; *q != '\0'; ++q)
hash = (hash * 2 + *q) % MPROF_HASH_SIZE; hash = (hash * 2 + *q) % MPROF_HASH_SIZE;
mtx_lock_spin(&mprof_mtx); mtx_lock_spin(&mprof_mtx);
n = hash; for (mpp = mprof_hash[hash]; mpp != NULL; mpp = mpp->next)
while ((mpp = mprof_hash[n]) != NULL) {
if (mpp->line == line && strcmp(mpp->file, p) == 0) if (mpp->line == line && strcmp(mpp->file, p) == 0)
break; break;
n = (n + 1) % MPROF_HASH_SIZE;
}
if (mpp == NULL) { if (mpp == NULL) {
/* Just exit if we cannot get a trace buffer */ /* Just exit if we cannot get a trace buffer */
if (first_free_mprof_buf >= NUM_MPROF_BUFFERS) { if (first_free_mprof_buf >= NUM_MPROF_BUFFERS) {
@ -370,9 +362,11 @@ _mtx_unlock_flags(struct mtx *m, int opts, const char *file, int line)
mpp->name = mtx_name(m); mpp->name = mtx_name(m);
mpp->file = p; mpp->file = p;
mpp->line = line; mpp->line = line;
mutex_prof_collisions += n - hash; mpp->next = mprof_hash[hash];
if (mprof_hash[hash] != NULL)
++mutex_prof_collisions;
mprof_hash[hash] = mpp;
++mutex_prof_records; ++mutex_prof_records;
mprof_hash[hash] = mpp;
} }
/* /*
* Record if the mutex has been held longer now than ever * Record if the mutex has been held longer now than ever

26
sys/kern/subr_turnstile.c
View File

@ -219,6 +219,7 @@ struct mutex_prof {
#define MPROF_CNT 2 #define MPROF_CNT 2
#define MPROF_AVG 3 #define MPROF_AVG 3
u_int64_t counter[4]; u_int64_t counter[4];
struct mutex_prof *next;
}; };
/* /*
@ -227,10 +228,10 @@ struct mutex_prof {
* *
* Note: NUM_MPROF_BUFFERS must be smaller than MPROF_HASH_SIZE. * Note: NUM_MPROF_BUFFERS must be smaller than MPROF_HASH_SIZE.
*/ */
#define NUM_MPROF_BUFFERS 4096 #define NUM_MPROF_BUFFERS 1000
static struct mutex_prof mprof_buf[NUM_MPROF_BUFFERS]; static struct mutex_prof mprof_buf[NUM_MPROF_BUFFERS];
static int first_free_mprof_buf; static int first_free_mprof_buf;
#define MPROF_HASH_SIZE 32771 #define MPROF_HASH_SIZE 1009
static struct mutex_prof *mprof_hash[MPROF_HASH_SIZE]; static struct mutex_prof *mprof_hash[MPROF_HASH_SIZE];
static int mutex_prof_acquisitions; static int mutex_prof_acquisitions;
@ -256,13 +257,7 @@ SYSCTL_INT(_debug_mutex_prof, OID_AUTO, collisions, CTLFLAG_RD,
* mprof_mtx protects the profiling buffers and the hash. * mprof_mtx protects the profiling buffers and the hash.
*/ */
static struct mtx mprof_mtx; static struct mtx mprof_mtx;
MTX_SYSINIT(mprof, &mprof_mtx, "mutex profiling lock", MTX_SPIN | MTX_QUIET);
static void
mprof_init(void *arg __unused)
{
mtx_init(&mprof_mtx, "mutex profiling lock", MTX_SPIN | MTX_QUIET);
}
SYSINIT(mprofinit, SI_SUB_LOCK, SI_ORDER_ANY, mprof_init, NULL);
static u_int64_t static u_int64_t
nanoseconds(void) nanoseconds(void)
@ -340,7 +335,7 @@ _mtx_unlock_flags(struct mtx *m, int opts, const char *file, int line)
struct mutex_prof *mpp; struct mutex_prof *mpp;
u_int64_t acqtime, now; u_int64_t acqtime, now;
const char *p, *q; const char *p, *q;
volatile u_int hash, n; volatile u_int hash;
now = nanoseconds(); now = nanoseconds();
acqtime = m->acqtime; acqtime = m->acqtime;
@ -354,12 +349,9 @@ _mtx_unlock_flags(struct mtx *m, int opts, const char *file, int line)
for (hash = line, q = p; *q != '\0'; ++q) for (hash = line, q = p; *q != '\0'; ++q)
hash = (hash * 2 + *q) % MPROF_HASH_SIZE; hash = (hash * 2 + *q) % MPROF_HASH_SIZE;
mtx_lock_spin(&mprof_mtx); mtx_lock_spin(&mprof_mtx);
n = hash; for (mpp = mprof_hash[hash]; mpp != NULL; mpp = mpp->next)
while ((mpp = mprof_hash[n]) != NULL) {
if (mpp->line == line && strcmp(mpp->file, p) == 0) if (mpp->line == line && strcmp(mpp->file, p) == 0)
break; break;
n = (n + 1) % MPROF_HASH_SIZE;
}
if (mpp == NULL) { if (mpp == NULL) {
/* Just exit if we cannot get a trace buffer */ /* Just exit if we cannot get a trace buffer */
if (first_free_mprof_buf >= NUM_MPROF_BUFFERS) { if (first_free_mprof_buf >= NUM_MPROF_BUFFERS) {
@ -370,9 +362,11 @@ _mtx_unlock_flags(struct mtx *m, int opts, const char *file, int line)
mpp->name = mtx_name(m); mpp->name = mtx_name(m);
mpp->file = p; mpp->file = p;
mpp->line = line; mpp->line = line;
mutex_prof_collisions += n - hash; mpp->next = mprof_hash[hash];
if (mprof_hash[hash] != NULL)
++mutex_prof_collisions;
mprof_hash[hash] = mpp;
++mutex_prof_records; ++mutex_prof_records;
mprof_hash[hash] = mpp;
} }
/* /*
* Record if the mutex has been held longer now than ever * Record if the mutex has been held longer now than ever