From 3c7b72ddca9ce85a9d1e8a98fd0996b74597b5ae Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Sat, 14 May 2022 08:50:10 +0200 Subject: thread-pool: optimize scheduling of completion bottom half The completion bottom half was scheduled within the pool->lock critical section. That actually results in worse performance, because the worker thread can run its own small critical section and go to sleep before the bottom half starts running. Note that this simple change does not produce an improvement without changing the thread pool QemuSemaphore to a condition variable. Reviewed-by: Stefan Hajnoczi Reviewed-by: Nicolas Saenz Julienne Message-Id: <20220514065012.1149539-2-pbonzini@redhat.com> Signed-off-by: Paolo Bonzini --- util/thread-pool.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'util/thread-pool.c') diff --git a/util/thread-pool.c b/util/thread-pool.c index 196835b4d3..4979f30ca3 100644 --- a/util/thread-pool.c +++ b/util/thread-pool.c @@ -127,9 +127,8 @@ static void *worker_thread(void *opaque) smp_wmb(); req->state = THREAD_DONE; - qemu_mutex_lock(&pool->lock); - qemu_bh_schedule(pool->completion_bh); + qemu_mutex_lock(&pool->lock); } pool->cur_threads--; -- cgit v1.2.3