From patchwork Fri Jan 9 10:16:59 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Hajnoczi X-Patchwork-Id: 427020 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 26AB3140142 for ; Fri, 9 Jan 2015 21:29:16 +1100 (AEDT) Received: from localhost ([::1]:49906 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Y9Woc-0000Ct-A6 for incoming@patchwork.ozlabs.org; Fri, 09 Jan 2015 05:29:14 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:53877) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Y9Wdr-0005gL-UD for qemu-devel@nongnu.org; Fri, 09 Jan 2015 05:18:09 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Y9Wdo-0001jo-Or for qemu-devel@nongnu.org; Fri, 09 Jan 2015 05:18:07 -0500 Received: from mx1.redhat.com ([209.132.183.28]:39094) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Y9Wdo-0001jK-GY for qemu-devel@nongnu.org; Fri, 09 Jan 2015 05:18:04 -0500 Received: from int-mx10.intmail.prod.int.phx2.redhat.com (int-mx10.intmail.prod.int.phx2.redhat.com [10.5.11.23]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id t09AHvOo018410 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Fri, 9 Jan 2015 05:17:57 -0500 Received: from localhost (ovpn-112-80.ams2.redhat.com [10.36.112.80]) by int-mx10.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id t09AHtH7008237; Fri, 9 Jan 2015 05:17:56 -0500 From: Stefan Hajnoczi To: Date: Fri, 9 Jan 2015 10:16:59 +0000 Message-Id: <1420798626-11428-20-git-send-email-stefanha@redhat.com> In-Reply-To: <1420798626-11428-1-git-send-email-stefanha@redhat.com> References: <1420798626-11428-1-git-send-email-stefanha@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.23 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x X-Received-From: 209.132.183.28 Cc: Peter Maydell , Peter Lieven , Stefan Hajnoczi , Paolo Bonzini Subject: [Qemu-devel] [PULL 19/26] coroutine: try harder not to delete coroutines X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org From: Peter Lieven 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 Signed-off-by: Paolo Bonzini Reviewed-by: Fam Zheng Message-id: 1417518350-6167-8-git-send-email-pbonzini@redhat.com Signed-off-by: Stefan Hajnoczi --- 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);