From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9163BCDB482 for ; Thu, 19 Oct 2023 13:02:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345779AbjJSNC0 (ORCPT ); Thu, 19 Oct 2023 09:02:26 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37342 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235376AbjJSNCR (ORCPT ); Thu, 19 Oct 2023 09:02:17 -0400 Received: from mail-io1-xd2a.google.com (mail-io1-xd2a.google.com [IPv6:2607:f8b0:4864:20::d2a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 286516EA0 for ; Thu, 19 Oct 2023 06:01:29 -0700 (PDT) Received: by mail-io1-xd2a.google.com with SMTP id ca18e2360f4ac-79fab2caf70so69983239f.1 for ; Thu, 19 Oct 2023 06:01:29 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20230601.gappssmtp.com; s=20230601; t=1697720487; x=1698325287; darn=vger.kernel.org; h=content-transfer-encoding:subject:from:to:content-language :user-agent:mime-version:date:message-id:from:to:cc:subject:date :message-id:reply-to; bh=pG3rynEGwYqH3CMUWHGTYB5p02H0+uBp6/zRGHa85uY=; b=npfcnMakid1ce+/YaF09VqrHQCB/zue7Xim+/0Ir/wFOSJu35MUTRsGKs7AWE6ubSx tTsKAqZSqqNbHcxkwjOwINkbj7ABTgIW1jewgMOHBFFgB7wO8kPNpY7/+rNEcbh5lcnO lD2o+fzYe1wi13xdZFerWQ00+WBrQn6+LNG7VfZ22/Om0nq+6VcsIja+usDA1LYSjQhT iJPnyCWlDnpbNtKHhZw6cUcEr8Ix/R2Zu0e+XwmhMHBb2+Nh+Ayl1EjfXg7cq8NfHHL9 5QaThsZhk+TUV4as2QUher4z6eWs1glpHX2AfVQy+RKKdBmNEsBefTfp4d/EwS2eUzKc QHsQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1697720487; x=1698325287; h=content-transfer-encoding:subject:from:to:content-language :user-agent:mime-version:date:message-id:x-gm-message-state:from:to :cc:subject:date:message-id:reply-to; bh=pG3rynEGwYqH3CMUWHGTYB5p02H0+uBp6/zRGHa85uY=; b=d9KIrCqIZi1tPPc1fqKCbNOXjS+uBydHvcmRb787SkfuSmL3eg2XdV7rjySAjSbwUp 6UPeWiU6IOjw99gppTEZ+h+YATSEAARO7IiynQDycD5VS/NPm127efSKKgkulLLzJ2v2 65myR8mL6AnXO/BiTUwHSGcQWZprRyMbzWPBssnnLlUuw5pBNiSIgoX7UFpF/FF7XTAq tO7rGMDjHuqJgP9exgjgO038wXmOtdDXM2lz+qmCfi9rF8IpDB3xEdtEo72rDclkVHHQ IdcdVBdYyHfigSTLEWCIRgtB+JO7LXADqtLOx+7MnRLL2HwofkQEmhzyhDHrKWnlbez/ XmpQ== X-Gm-Message-State: AOJu0Yxy+oCcjYR/UrQNIzyWlBLTlHljH77b4qqyRRx6iHjiHinNfJcP 1TiLNSsZobNyXQ6iHg6dgf+9+PsEo4xQQHUn5ZTsjw== X-Google-Smtp-Source: AGHT+IHbDoUwOM4L+vUfE7wjfVwFryAH3von/T6K+kAdC0US6DRJlSyIPLPVKTztL8n/qisCXxDbwA== X-Received: by 2002:a92:d2ca:0:b0:34f:a4f0:4fc4 with SMTP id w10-20020a92d2ca000000b0034fa4f04fc4mr2326108ilg.2.1697720487517; Thu, 19 Oct 2023 06:01:27 -0700 (PDT) Received: from [192.168.1.136] ([198.8.77.194]) by smtp.gmail.com with ESMTPSA id k9-20020aa790c9000000b006be047268d5sm5223820pfk.174.2023.10.19.06.01.26 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 19 Oct 2023 06:01:26 -0700 (PDT) Message-ID: Date: Thu, 19 Oct 2023 07:01:26 -0600 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Content-Language: en-US To: io-uring From: Jens Axboe Subject: [PATCH] io_uring/poll: use IOU_F_TWQ_LAZY_WAKE for wakeups Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org With poll triggered retries, each event trigger will cause a task_work item to be added for processing. If the ring is setup with IORING_SETUP_DEFER_TASKRUN and a task is waiting on multiple events to complete, any task_work addition will wake the task for processing these items. This can cause more context switches than we would like, if the application is deliberately waiting on multiple items to increase efficiency. For example, if an application has receive multishot armed for sockets and wants to wait for N to complete within M usec of time, we should not be waking up and processing these items until we have all the events we asked for. By switching the poll trigger to lazy wake, we'll process them when they are all ready, in one swoop, rather than wake multiple times only to process one and then go back to sleep. At some point we probably want to look at just making the lazy wake the default, but for now, let's just selectively enable it where it makes sense. Signed-off-by: Jens Axboe --- diff --git a/io_uring/poll.c b/io_uring/poll.c index 4c360ba8793a..d38d05edb4fa 100644 --- a/io_uring/poll.c +++ b/io_uring/poll.c @@ -370,7 +370,7 @@ static void __io_poll_execute(struct io_kiocb *req, int mask) req->io_task_work.func = io_poll_task_func; trace_io_uring_task_add(req, mask); - io_req_task_work_add(req); + __io_req_task_work_add(req, IOU_F_TWQ_LAZY_WAKE); } static inline void io_poll_execute(struct io_kiocb *req, int res) -- Jens Axboe