SUNRPC: Micro-optimize __rpc_execute

The common case: There are 13 to 14 actions per RPC, and tk_callback
is non-NULL in only one of them. There's no need to store a NULL in
the tk_callback field during each FSM step.

This slightly improves throughput results in dbench and other multi-
threaded benchmarks on my two-socket client on 56Gb InfiniBand, but
will probably be inconsequential on slower systems.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
This commit is contained in:
Chuck Lever 2018-01-03 15:38:49 -05:00 committed by Anna Schumaker
parent cf08d6f2e6
commit 21ead9ff3d

View file

@ -755,21 +755,19 @@ static void __rpc_execute(struct rpc_task *task)
void (*do_action)(struct rpc_task *);
/*
* Execute any pending callback first.
* Perform the next FSM step or a pending callback.
*
* tk_action may be NULL if the task has been killed.
* In particular, note that rpc_killall_tasks may
* do this at any time, so beware when dereferencing.
*/
do_action = task->tk_callback;
task->tk_callback = NULL;
if (do_action == NULL) {
/*
* Perform the next FSM step.
* tk_action may be NULL if the task has been killed.
* In particular, note that rpc_killall_tasks may
* do this at any time, so beware when dereferencing.
*/
do_action = task->tk_action;
if (do_action == NULL)
break;
do_action = task->tk_action;
if (task->tk_callback) {
do_action = task->tk_callback;
task->tk_callback = NULL;
}
if (!do_action)
break;
trace_rpc_task_run_action(task->tk_client, task, do_action);
do_action(task);