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Add rudimentary profiling of the hash table used in the in the umtx code to

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hold active lock queues.

Reviewed by:	attilio
Approved by:	davidxu, gnn (mentor)
MFC after:	3 weeks
This commit is contained in:
Davide Italiano 2012-03-16 20:32:11 +00:00
parent 786645078b
commit c6111de55d
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=233045
3 changed files with 55 additions and 1 deletions
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4
sys/conf/NOTES
View File

@ -274,6 +274,8 @@ options SX_NOINLINE
# frequency.
# TURNSTILE_PROFILING enables rudimentary profiling of the hash table
# used to hold active lock queues.
# UMTX_PROFILING enables rudimentary profiling of the hash table used
to hold active lock queues.
# WITNESS enables the witness code which detects deadlocks and cycles
# during locking operations.
# WITNESS_KDB causes the witness code to drop into the kernel debugger if
@ -297,8 +299,8 @@ options MPROF_HASH_SIZE="1543"
# Profiling for internal hash tables.
options SLEEPQUEUE_PROFILING
options TURNSTILE_PROFILING
options UMTX_PROFILING
#####################################################################
# COMPATIBILITY OPTIONS

1
sys/conf/options
View File

@ -186,6 +186,7 @@ SYSVSEM opt_sysvipc.h
SYSVSHM opt_sysvipc.h
SW_WATCHDOG opt_watchdog.h
TURNSTILE_PROFILING
UMTX_PROFILING
VFS_AIO
VFS_ALLOW_NONMPSAFE
VERBOSE_SYSINIT opt_global.h

51
sys/kern/kern_umtx.c
View File

@ -29,6 +29,8 @@
__FBSDID("$FreeBSD$");
#include "opt_compat.h"
#include "opt_umtx_profiling.h"
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/limits.h>
@ -154,6 +156,10 @@ struct umtxq_chain {
/* All PI in the list */
TAILQ_HEAD(,umtx_pi) uc_pi_list;
#ifdef UMTX_PROFILING
int length;
int max_length;
#endif
};
#define UMTXQ_LOCKED_ASSERT(uc) mtx_assert(&(uc)->uc_lock, MA_OWNED)
@ -190,6 +196,12 @@ static SYSCTL_NODE(_debug, OID_AUTO, umtx, CTLFLAG_RW, 0, "umtx debug");
SYSCTL_INT(_debug_umtx, OID_AUTO, umtx_pi_allocated, CTLFLAG_RD,
&umtx_pi_allocated, 0, "Allocated umtx_pi");
#ifdef UMTX_PROFILING
static long max_length;
SYSCTL_LONG(_debug_umtx, OID_AUTO, max_length, CTLFLAG_RD, &max_length, 0, "max_length");
static SYSCTL_NODE(_debug_umtx, OID_AUTO, chains, CTLFLAG_RD, 0, "umtx chain stats");
#endif
static void umtxq_sysinit(void *);
static void umtxq_hash(struct umtx_key *key);
static struct umtxq_chain *umtxq_getchain(struct umtx_key *key);
@ -215,6 +227,27 @@ SYSINIT(umtx, SI_SUB_EVENTHANDLER+1, SI_ORDER_MIDDLE, umtxq_sysinit, NULL);
static struct mtx umtx_lock;
#ifdef UMTX_PROFILING
static void
umtx_init_profiling(void)
{
struct sysctl_oid *chain_oid;
char chain_name[10];
int i;
for (i = 0; i < UMTX_CHAINS; ++i) {
snprintf(chain_name, sizeof(chain_name), "%d", i);
chain_oid = SYSCTL_ADD_NODE(NULL,
SYSCTL_STATIC_CHILDREN(_debug_umtx_chains), OID_AUTO,
chain_name, CTLFLAG_RD, NULL, "umtx hash stats");
SYSCTL_ADD_INT(NULL, SYSCTL_CHILDREN(chain_oid), OID_AUTO,
"max_length0", CTLFLAG_RD, &umtxq_chains[0][i].max_length, 0, NULL);
SYSCTL_ADD_INT(NULL, SYSCTL_CHILDREN(chain_oid), OID_AUTO,
"max_length1", CTLFLAG_RD, &umtxq_chains[1][i].max_length, 0, NULL);
}
}
#endif
static void
umtxq_sysinit(void *arg __unused)
{
@ -232,8 +265,15 @@ umtxq_sysinit(void *arg __unused)
TAILQ_INIT(&umtxq_chains[i][j].uc_pi_list);
umtxq_chains[i][j].uc_busy = 0;
umtxq_chains[i][j].uc_waiters = 0;
#ifdef UMTX_PROFILING
umtxq_chains[i][j].length = 0;
umtxq_chains[i][j].max_length = 0;
#endif
}
}
#ifdef UMTX_PROFILING
umtx_init_profiling();
#endif
mtx_init(&umtx_lock, "umtx lock", NULL, MTX_SPIN);
EVENTHANDLER_REGISTER(process_exec, umtx_exec_hook, NULL,
EVENTHANDLER_PRI_ANY);
@ -384,6 +424,14 @@ umtxq_insert_queue(struct umtx_q *uq, int q)
TAILQ_INSERT_TAIL(&uh->head, uq, uq_link);
uh->length++;
#ifdef UMTX_PROFILING
uc->length++;
if (uc->length > uc->max_length) {
uc->max_length = uc->length;
if (uc->max_length > max_length)
max_length = uc->max_length;
}
#endif
uq->uq_flags |= UQF_UMTXQ;
uq->uq_cur_queue = uh;
return;
@ -401,6 +449,9 @@ umtxq_remove_queue(struct umtx_q *uq, int q)
uh = uq->uq_cur_queue;
TAILQ_REMOVE(&uh->head, uq, uq_link);
uh->length--;
#ifdef UMTX_PROFILING
uc->length--;
#endif
uq->uq_flags &= ~UQF_UMTXQ;
if (TAILQ_EMPTY(&uh->head)) {
KASSERT(uh->length == 0,