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authorMohit Agrawal <moagrawa@redhat.com>2017-10-20 12:39:29 +0530
committerAmar Tumballi <amarts@redhat.com>2017-12-12 09:05:56 +0000
commit430484c92ab5a6234958d1143e0bb14aeb0cd1c0 (patch)
tree0fb39e2a1c9be94396736d76b9aaababf232821b /rpc
parent8483ed87165c1695b513e223549d33d2d63891d9 (diff)
glusterfs: Use gcc builtin ATOMIC operator to increase/decreate refcount.
Problem: In glusterfs code base we call mutex_lock/unlock to take reference/dereference for a object.Sometime it could be reason for lock contention also. Solution: There is no need to use mutex to increase/decrease ref counter, instead of using mutex use gcc builtin ATOMIC operation. Test: I have not observed yet how much performance gain after apply this patch specific to glusterfs but i have tested same with below small program(mutex and atomic both) and get good difference. static int numOuterLoops; static void * threadFunc(void *arg) { int j; for (j = 0; j < numOuterLoops; j++) { __atomic_add_fetch (&glob, 1,__ATOMIC_ACQ_REL); } return NULL; } int main(int argc, char *argv[]) { int opt, s, j; int numThreads; pthread_t *thread; int verbose; int64_t n = 0; if (argc < 2 ) { printf(" Please provide 2 args Num of threads && Outer Loop\n"); exit (-1); } numThreads = atoi(argv[1]); numOuterLoops = atoi (argv[2]); if (1) { printf("\tthreads: %d; outer loops: %d;\n", numThreads, numOuterLoops); } thread = calloc(numThreads, sizeof(pthread_t)); if (thread == NULL) { printf ("calloc error so exit\n"); exit (-1); } __atomic_store (&glob, &n, __ATOMIC_RELEASE); for (j = 0; j < numThreads; j++) { s = pthread_create(&thread[j], NULL, threadFunc, NULL); if (s != 0) { printf ("pthread_create failed so exit\n"); exit (-1); } } for (j = 0; j < numThreads; j++) { s = pthread_join(thread[j], NULL); if (s != 0) { printf ("pthread_join failed so exit\n"); exit (-1); } } printf("glob value is %ld\n",__atomic_load_n (&glob,__ATOMIC_RELAXED)); exit(0); } time ./thr_count 800 800000 threads: 800; outer loops: 800000; glob value is 640000000 real 1m10.288s user 0m57.269s sys 3m31.565s time ./thr_count_atomic 800 800000 threads: 800; outer loops: 800000; glob value is 640000000 real 0m20.313s user 1m20.558s sys 0m0.028 Change-Id: Ie5030a52ea264875e002e108dd4b207b15ab7cc7 Signed-off-by: Mohit Agrawal <moagrawa@redhat.com>
Diffstat (limited to 'rpc')
-rw-r--r--rpc/rpc-lib/src/rpc-clnt.c15
-rw-r--r--rpc/rpc-lib/src/rpc-clnt.h2
-rw-r--r--rpc/rpc-lib/src/rpc-transport.c12
-rw-r--r--rpc/rpc-lib/src/rpc-transport.h2
4 files changed, 9 insertions, 22 deletions
diff --git a/rpc/rpc-lib/src/rpc-clnt.c b/rpc/rpc-lib/src/rpc-clnt.c
index cb59408dcf6..06aed0a80ae 100644
--- a/rpc/rpc-lib/src/rpc-clnt.c
+++ b/rpc/rpc-lib/src/rpc-clnt.c
@@ -1740,11 +1740,8 @@ rpc_clnt_ref (struct rpc_clnt *rpc)
{
if (!rpc)
return NULL;
- pthread_mutex_lock (&rpc->lock);
- {
- rpc->refcount++;
- }
- pthread_mutex_unlock (&rpc->lock);
+
+ GF_ATOMIC_INC (rpc->refcount);
return rpc;
}
@@ -1806,11 +1803,9 @@ rpc_clnt_unref (struct rpc_clnt *rpc)
if (!rpc)
return NULL;
- pthread_mutex_lock (&rpc->lock);
- {
- count = --rpc->refcount;
- }
- pthread_mutex_unlock (&rpc->lock);
+
+ count = GF_ATOMIC_DEC (rpc->refcount);
+
if (!count) {
rpc_clnt_trigger_destroy (rpc);
return NULL;
diff --git a/rpc/rpc-lib/src/rpc-clnt.h b/rpc/rpc-lib/src/rpc-clnt.h
index 428ffb80650..6503ca5a573 100644
--- a/rpc/rpc-lib/src/rpc-clnt.h
+++ b/rpc/rpc-lib/src/rpc-clnt.h
@@ -187,7 +187,7 @@ typedef struct rpc_clnt {
struct mem_pool *saved_frames_pool;
glusterfs_ctx_t *ctx;
- int refcount;
+ gf_atomic_t refcount;
int auth_null;
char disabled;
xlator_t *owner;
diff --git a/rpc/rpc-lib/src/rpc-transport.c b/rpc/rpc-lib/src/rpc-transport.c
index 40b5917f9b8..40c41ab7016 100644
--- a/rpc/rpc-lib/src/rpc-transport.c
+++ b/rpc/rpc-lib/src/rpc-transport.c
@@ -493,11 +493,7 @@ rpc_transport_ref (rpc_transport_t *this)
GF_VALIDATE_OR_GOTO("rpc_transport", this, fail);
- pthread_mutex_lock (&this->lock);
- {
- this->refcount ++;
- }
- pthread_mutex_unlock (&this->lock);
+ GF_ATOMIC_INC (this->refcount);
return_this = this;
fail:
@@ -513,11 +509,7 @@ rpc_transport_unref (rpc_transport_t *this)
GF_VALIDATE_OR_GOTO("rpc_transport", this, fail);
- pthread_mutex_lock (&this->lock);
- {
- refcount = --this->refcount;
- }
- pthread_mutex_unlock (&this->lock);
+ refcount = GF_ATOMIC_DEC (this->refcount);
if (refcount == 0) {
if (this->mydata)
diff --git a/rpc/rpc-lib/src/rpc-transport.h b/rpc/rpc-lib/src/rpc-transport.h
index 33f474e42c6..332efb45c25 100644
--- a/rpc/rpc-lib/src/rpc-transport.h
+++ b/rpc/rpc-lib/src/rpc-transport.h
@@ -184,7 +184,7 @@ struct rpc_transport {
void *xl; /* Used for THIS */
void *mydata;
pthread_mutex_t lock;
- int32_t refcount;
+ gf_atomic_t refcount;
int32_t outstanding_rpc_count;