From patchwork Tue Aug 4 05:28:01 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Hajnoczi X-Patchwork-Id: 277162 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id DC518C433E0 for ; Tue, 4 Aug 2020 05:29:02 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id CFFC32064B for ; Tue, 4 Aug 2020 05:29:02 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="CtkoZkXZ" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CFFC32064B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:59584 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1k2pVV-00068T-SY for qemu-devel@archiver.kernel.org; Tue, 04 Aug 2020 01:29:01 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:45476) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1k2pUl-0005NZ-Da for qemu-devel@nongnu.org; Tue, 04 Aug 2020 01:28:15 -0400 Received: from us-smtp-1.mimecast.com ([207.211.31.81]:43147 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 1k2pUi-0004fa-E8 for qemu-devel@nongnu.org; Tue, 04 Aug 2020 01:28:15 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1596518891; 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=FYbdF9A59yOuFAqIJal7DuJ8EsPliIp4vtn9QbCP0Yk=; b=CtkoZkXZ0UdrTjf+N+B2vdze10c1Xph15dM+oqYYJZfM38OD/GfbOgZEIzOY1bqoKLK7VR 6KqT+xSbU1z2VjElraZO63ExBrfGIOOMmRBFrqgLiGQYO8ZizwzmxE1mqqs/smfRMZAJ3U DO5StBKJNQylDsyCV/uhH/d7Gt9fpgg= 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-205-oI8sd39iM7yo7NhTWWIPZA-1; Tue, 04 Aug 2020 01:28:09 -0400 X-MC-Unique: oI8sd39iM7yo7NhTWWIPZA-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 9CD39108088A; Tue, 4 Aug 2020 05:28:08 +0000 (UTC) Received: from localhost (ovpn-112-116.ams2.redhat.com [10.36.112.116]) by smtp.corp.redhat.com (Postfix) with ESMTP id 516505D9F7; Tue, 4 Aug 2020 05:28:05 +0000 (UTC) From: Stefan Hajnoczi To: qemu-devel@nongnu.org Subject: [PATCH 0/3] aio-posix: keep aio_notify_me disabled during polling Date: Tue, 4 Aug 2020 06:28:01 +0100 Message-Id: <20200804052804.1165291-1-stefanha@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Received-SPF: pass client-ip=207.211.31.81; envelope-from=stefanha@redhat.com; helo=us-smtp-delivery-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/08/04 01:01:15 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -30 X-Spam_score: -3.1 X-Spam_bar: --- X-Spam_report: (-3.1 / 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_H3=-0.01, RCVD_IN_MSPIKE_WL=-0.01, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable 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 , Stefan Hajnoczi , qemu-block@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" 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%. aio_compute_timeout() is now called twice if aio_poll() needs to block, which means an extra qemu_clock_get_ns() call is made when there is an active timer. An alternative would be to set timeout = 0 if ctx->notified is true before blocking, but going around the event loop again could slow things down more. 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 | 56 ++++++++++++++++++++++++------------------------ util/async.c | 22 +++++++++---------- 2 files changed, 38 insertions(+), 40 deletions(-) -- 2.26.2