From patchwork Wed Aug 5 10:00:48 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Hajnoczi X-Patchwork-Id: 1341178 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org (client-ip=209.51.188.17; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Authentication-Results: ozlabs.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: ozlabs.org; dkim=fail reason="signature verification failed" (1024-bit key; unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256 header.s=mimecast20190719 header.b=FV2XdHdo; dkim-atps=neutral Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 4BM6dV3T3rz9sPB for ; Wed, 5 Aug 2020 20:03:26 +1000 (AEST) Received: from localhost ([::1]:44958 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1k3GGa-00088V-6P for incoming@patchwork.ozlabs.org; Wed, 05 Aug 2020 06:03:24 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:37458) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1k3GEJ-0005iF-5Q for qemu-devel@nongnu.org; Wed, 05 Aug 2020 06:01:03 -0400 Received: from us-smtp-1.mimecast.com ([205.139.110.61]:47160 helo=us-smtp-delivery-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1k3GEH-0000Rm-59 for qemu-devel@nongnu.org; Wed, 05 Aug 2020 06:01:02 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1596621659; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=Pko9KcEGYzgbCxo8HxvXntBgxu0EM15eGioBrTr77ns=; b=FV2XdHdohWn1kQLTJ7EfQIr3sDYv7O99glbvbLOJzIQdpO79i2G89V0YQ9bmzkzeWpcRl8 geb16xkoJRqiKhYn5iAUw8LLS7Pg25OxFRvyY4rFomxC1Cv214dTiE7o9BeLeQA2bbACKw rVwfkpYGpHqNbrkcOKXE5q2syGHbjYM= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-504-JCnRwi9pNYeFIx9aRU9NcA-1; Wed, 05 Aug 2020 06:00:57 -0400 X-MC-Unique: JCnRwi9pNYeFIx9aRU9NcA-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 4F2348015F4; Wed, 5 Aug 2020 10:00:56 +0000 (UTC) Received: from localhost (ovpn-114-155.ams2.redhat.com [10.36.114.155]) by smtp.corp.redhat.com (Postfix) with ESMTP id 0397B1A922; Wed, 5 Aug 2020 10:00:52 +0000 (UTC) From: Stefan Hajnoczi To: qemu-devel@nongnu.org Subject: [PATCH v2 0/3] aio-posix: keep aio_notify_me disabled during polling Date: Wed, 5 Aug 2020 11:00:48 +0100 Message-Id: <20200805100051.361547-1-stefanha@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Received-SPF: pass client-ip=205.139.110.61; envelope-from=stefanha@redhat.com; helo=us-smtp-delivery-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/08/05 04:10:11 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -40 X-Spam_score: -4.1 X-Spam_bar: ---- X-Spam_report: (-4.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-1, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Fam Zheng , Paolo Bonzini , qemu-block@nongnu.org, Stefan Hajnoczi Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" v2: * Added smp_mb() in aio_notify_accept() [Paolo] * Added comments about memory barrier pairing [Paolo] * Eliminated extra aio_compute_timeout() before calling ppoll() This patch series eliminates ctx->notifier EventNotifier activity when aio_poll() is in polling mode. There is no need to use the EventNotifier since a polling handler can detect that aio_notify() has been called by monitoring a field in memory instead. Optimizing out the EventNotifier calls improves null-co random read 4KB iodepth=1 IOPS by 18%. I have not modified docs/spin/aio_notify*.promela because I'm not familiar with the SPIN model checker. Stefan Hajnoczi (3): async: rename event_notifier_dummy_cb/poll() async: always set ctx->notified in aio_notify() aio-posix: keep aio_notify_me disabled during polling util/aio-posix.c | 59 +++++++++++++++++++++++++----------------------- util/async.c | 36 ++++++++++++++++++----------- 2 files changed, 54 insertions(+), 41 deletions(-)