Author: davide
Date: Fri Mar 16 20:32:11 2012
New Revision: 233045
URL: http://svn.freebsd.org/changeset/base/233045
Log:
Add rudimentary profiling of the hash table used in the in the umtx code to
hold active lock queues.
Reviewed by: attilio
Approved by: davidxu, gnn (mentor)
MFC after: 3 weeks
Modified:
head/sys/conf/NOTES
head/sys/conf/options
head/sys/kern/kern_umtx.c
Modified: head/sys/conf/NOTES
==============================================================================
--- head/sys/conf/NOTES Fri Mar 16 20:24:30 2012 (r233044)
+++ head/sys/conf/NOTES Fri Mar 16 20:32:11 2012 (r233045)
@@ -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
Modified: head/sys/conf/options
==============================================================================
--- head/sys/conf/options Fri Mar 16 20:24:30 2012 (r233044)
+++ head/sys/conf/options Fri Mar 16 20:32:11 2012 (r233045)
@@ -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
Modified: head/sys/kern/kern_umtx.c
==============================================================================
--- head/sys/kern/kern_umtx.c Fri Mar 16 20:24:30 2012 (r233044)
+++ head/sys/kern/kern_umtx.c Fri Mar 16 20:32:11 2012 (r233045)
@@ -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, umt
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_
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, in
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, in
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,
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