46 lines
1.5 KiB
Diff
46 lines
1.5 KiB
Diff
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From c84bb01c0c56cadb70a95c874b32ed85b8177504 Mon Sep 17 00:00:00 2001
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From: tangbinzy <tangbin_yewu@cmss.chinamobile.com>
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Date: Tue, 26 Sep 2023 06:41:50 +0000
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Subject: [PATCH] thread-pool: optimize scheduling of completion bottom half
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mainline inclusion commit 3c7b72ddca9ce85a9d1e8a98fd0996b74597b5ae category:
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bugfix
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---------------------------------------------------------------
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The completion bottom half was scheduled within the pool->lock
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critical section. That actually results in worse performance,
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because the worker thread can run its own small critical section
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and go to sleep before the bottom half starts running.
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Note that this simple change does not produce an improvement without
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changing the thread pool QemuSemaphore to a condition variable.
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Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
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Reviewed-by: Nicolas Saenz Julienne <nsaenzju@redhat.com>
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Message-Id: <20220514065012.1149539-2-pbonzini@redhat.com>
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Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Signed-off-by: tangbinzy <tangbin_yewu@cmss.chinamobile.com>
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---
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util/thread-pool.c | 3 +--
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1 file changed, 1 insertion(+), 2 deletions(-)
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diff --git a/util/thread-pool.c b/util/thread-pool.c
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index d763cea505..7e9e2c178b 100644
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--- a/util/thread-pool.c
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+++ b/util/thread-pool.c
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@@ -108,9 +108,8 @@ static void *worker_thread(void *opaque)
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smp_wmb();
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req->state = THREAD_DONE;
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- qemu_mutex_lock(&pool->lock);
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-
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qemu_bh_schedule(pool->completion_bh);
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+ qemu_mutex_lock(&pool->lock);
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}
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pool->cur_threads--;
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--
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2.41.0.windows.1
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