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authorPeter Lieven <pl@kamp.de>2014-12-02 12:05:50 +0100
committerStefan Hajnoczi <stefanha@redhat.com>2015-01-13 13:43:29 +0000
commit51a2219bdceed16e81c6e2e2f08aed39c579728f (patch)
treee2fd7192232fa66fbed743b304a7b776d4140b93 /qemu-coroutine.c
parent66552b894bd68dd6539fb6d656ad2c21bdd6acbe (diff)
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coroutine: try harder not to delete coroutines
Placing coroutines on the global pool should be preferrable, because it can help all threads. But if the global pool is full, we can still try to save some allocations by stashing completed coroutines on the local pool. This is quite cheap too, because it does not require atomic operations, and provides a gain of 15% in the best case. Signed-off-by: Peter Lieven <pl@kamp.de> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Message-id: 1417518350-6167-8-git-send-email-pbonzini@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Diffstat (limited to 'qemu-coroutine.c')
-rw-r--r--qemu-coroutine.c9
1 files changed, 8 insertions, 1 deletions
diff --git a/qemu-coroutine.c b/qemu-coroutine.c
index da1b961..525247b 100644
--- a/qemu-coroutine.c
+++ b/qemu-coroutine.c
@@ -27,6 +27,7 @@ enum {
static QSLIST_HEAD(, Coroutine) release_pool = QSLIST_HEAD_INITIALIZER(pool);
static unsigned int release_pool_size;
static __thread QSLIST_HEAD(, Coroutine) alloc_pool = QSLIST_HEAD_INITIALIZER(pool);
+static __thread unsigned int alloc_pool_size;
static __thread Notifier coroutine_pool_cleanup_notifier;
static void coroutine_pool_cleanup(Notifier *n, void *value)
@@ -58,13 +59,14 @@ Coroutine *qemu_coroutine_create(CoroutineEntry *entry)
* release_pool_size and the actual size of release_pool. But
* it is just a heuristic, it does not need to be perfect.
*/
- release_pool_size = 0;
+ alloc_pool_size = atomic_xchg(&release_pool_size, 0);
QSLIST_MOVE_ATOMIC(&alloc_pool, &release_pool);
co = QSLIST_FIRST(&alloc_pool);
}
}
if (co) {
QSLIST_REMOVE_HEAD(&alloc_pool, pool_next);
+ alloc_pool_size--;
}
}
@@ -87,6 +89,11 @@ static void coroutine_delete(Coroutine *co)
atomic_inc(&release_pool_size);
return;
}
+ if (alloc_pool_size < POOL_BATCH_SIZE) {
+ QSLIST_INSERT_HEAD(&alloc_pool, co, pool_next);
+ alloc_pool_size++;
+ return;
+ }
}
qemu_coroutine_delete(co);