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[Qemu-devel] [PULL 19/26] coroutine: try harder not to delete coroutines
From: |
Stefan Hajnoczi |
Subject: |
[Qemu-devel] [PULL 19/26] coroutine: try harder not to delete coroutines |
Date: |
Fri, 9 Jan 2015 10:16:59 +0000 |
From: Peter Lieven <address@hidden>
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 <address@hidden>
Signed-off-by: Paolo Bonzini <address@hidden>
Reviewed-by: Fam Zheng <address@hidden>
Message-id: address@hidden
Signed-off-by: Stefan Hajnoczi <address@hidden>
---
qemu-coroutine.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
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);
--
2.1.0
- [Qemu-devel] [PULL 10/26] qemu-iotests: Add "_supported_os Linux" to 058, (continued)
- [Qemu-devel] [PULL 10/26] qemu-iotests: Add "_supported_os Linux" to 058, Stefan Hajnoczi, 2015/01/09
- [Qemu-devel] [PULL 08/26] .gitignore: Ignore generated "common.env", Stefan Hajnoczi, 2015/01/09
- [Qemu-devel] [PULL 11/26] tests/Makefile: Add check-block to make check on Linux, Stefan Hajnoczi, 2015/01/09
- [Qemu-devel] [PULL 13/26] coroutine-ucontext: use __thread, Stefan Hajnoczi, 2015/01/09
- [Qemu-devel] [PULL 12/26] qemu-iotests: Add supported os parameter for python tests, Stefan Hajnoczi, 2015/01/09
- [Qemu-devel] [PULL 14/26] qemu-thread: add per-thread atexit functions, Stefan Hajnoczi, 2015/01/09
- [Qemu-devel] [PULL 16/26] QSLIST: add lock-free operations, Stefan Hajnoczi, 2015/01/09
- [Qemu-devel] [PULL 15/26] test-coroutine: avoid overflow on 32-bit systems, Stefan Hajnoczi, 2015/01/09
- [Qemu-devel] [PULL 17/26] coroutine: rewrite pool to avoid mutex, Stefan Hajnoczi, 2015/01/09
- [Qemu-devel] [PULL 18/26] coroutine: drop qemu_coroutine_adjust_pool_size, Stefan Hajnoczi, 2015/01/09
- [Qemu-devel] [PULL 19/26] coroutine: try harder not to delete coroutines,
Stefan Hajnoczi <=
- [Qemu-devel] [PULL 20/26] block: limited request size in write zeroes unsupported path, Stefan Hajnoczi, 2015/01/09
- [Qemu-devel] [PULL 22/26] ide: Implement VPD response for ATAPI, Stefan Hajnoczi, 2015/01/09
- [Qemu-devel] [PULL 21/26] block: Split BLOCK_OP_TYPE_COMMIT to BLOCK_OP_TYPE_COMMIT_{SOURCE, TARGET}, Stefan Hajnoczi, 2015/01/09
- [Qemu-devel] [PULL 23/26] nvme: Fix get/set number of queues feature, Stefan Hajnoczi, 2015/01/09
- [Qemu-devel] [PULL 26/26] NVMe: Set correct VS Value for 1.1 Compliant Controllers, Stefan Hajnoczi, 2015/01/09
- [Qemu-devel] [PULL 25/26] MAINTAINERS: Add migration/block* to block subsystem, Stefan Hajnoczi, 2015/01/09
- [Qemu-devel] [PULL 24/26] MAINTAINERS: Update email addresses for Chrysostomos Nanakos, Stefan Hajnoczi, 2015/01/09
- Re: [Qemu-devel] [PULL 00/26] Block patches, Peter Maydell, 2015/01/10