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 X-Spam-Level: X-Spam-Status: No, score=-14.2 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=unavailable 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 904CFC48BDF for ; Tue, 22 Jun 2021 20:58:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 74E3960FF2 for ; Tue, 22 Jun 2021 20:58:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229955AbhFVVBG (ORCPT ); Tue, 22 Jun 2021 17:01:06 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50304 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229501AbhFVVBF (ORCPT ); Tue, 22 Jun 2021 17:01:05 -0400 Received: from mail-wm1-x329.google.com (mail-wm1-x329.google.com [IPv6:2a00:1450:4864:20::329]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4BF3AC061574; Tue, 22 Jun 2021 13:58:48 -0700 (PDT) Received: by mail-wm1-x329.google.com with SMTP id l18-20020a1ced120000b029014c1adff1edso2624213wmh.4; Tue, 22 Jun 2021 13:58:48 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=to:references:from:subject:message-id:date:user-agent:mime-version :in-reply-to:content-language:content-transfer-encoding; bh=6jHGy9hLjOpE8MKb9arulD/So2xoWxY8Pk/5qNqlwmg=; b=k24XzHvyVCEVHLQQkR11sf0rgnk+X6J/BG2oEoJ2cMimQv6dbgsqQJYKL7Zbt9i/S9 fXmDkaT4/EssoHMue2f36HUgHWyKm+ZqPEyCVFjCttTNvnhLbMhcKlon8oWqAI0XxXER PF7xQrMS7mMvK4wvBU6p3F/MPcc31oRZW7jEbUHk0ALnF9si2o9SatdxVpKt/uRVt+Ne y9+XCkVJBo/ZhoY3LjMZq1wCz3KQKh02pHNM/1ZkKcrT4LUETqdrnUBprEwkJ0+vL9Dh OQAom9f8ekZ5QDEJNbdoGJFNk0uVKDSsiclXfRCnHrED7yjW2CL5NUZ0AcXgAg6NvjKw HLug== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:to:references:from:subject:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=6jHGy9hLjOpE8MKb9arulD/So2xoWxY8Pk/5qNqlwmg=; b=OZzIwtHVMiu9xiTUB3wGv2kw5SjrxxDfwUmvQ/1yDg8qH1CrICYJlrtF6R99txRulx p9BvUUYvueh8hzXRVRXIX0bLyoDKBe41VZT/Rtn4sJDw1Lr7m1RzBTFgxqJ2ccEBvBJS gpn+mYTqjq9LqFFETRngjJsjQlUbsenIO0H/bQvMtzi0BCipTyBXRQjNJLlM9CUFfvge buCw918L0HoPPcJhdV9GTkdLCy1WBqUNEMrSAN7oUz3Sn8LHCTIiwe2UuipVcztDOmzU WTzkkPo+x4WeNxbEgcd+fFEs2kpmt+1U3mxyZMRaRC7M7MUkOBND90WZY38+OvtUqS3N uFJA== X-Gm-Message-State: AOAM531Ya4LUgrCBtQCppbmxb+BZeNt8iUUEmHMij5X4Hm2HEFIeriud MhvnNDh5842cpIGDWeAm9PobrrRgqYGnLXbZ X-Google-Smtp-Source: ABdhPJySV6KwpvbNc3jcqxn1AacRlD+KJFAdtp15YF1PHtlXawD/IReR8zVwDzA5HKRKvLlNMUtICg== X-Received: by 2002:a7b:c097:: with SMTP id r23mr6505032wmh.63.1624395526790; Tue, 22 Jun 2021 13:58:46 -0700 (PDT) Received: from [192.168.8.197] ([148.252.132.93]) by smtp.gmail.com with ESMTPSA id n4sm521048wrw.21.2021.06.22.13.58.45 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 22 Jun 2021 13:58:46 -0700 (PDT) To: Olivier Langlois , Jens Axboe , io-uring@vger.kernel.org, linux-kernel@vger.kernel.org References: From: Pavel Begunkov Subject: Re: [PATCH 2/2] io_uring: Create define to modify a SQPOLL parameter Message-ID: <985f8f73-ad30-855c-39d5-1d3841b43c10@gmail.com> Date: Tue, 22 Jun 2021 21:58:33 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.10.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 6/22/21 7:45 PM, Olivier Langlois wrote: > The magic number used to cap the number of entries extracted from an > io_uring instance SQ before moving to the other instances is an > interesting parameter to experiment with. Not particularly related to this patch, but the problem with this capping is that there is no reliable way to do request linking using shared sqpoll. It may break a link in half (or in N parts for long links) and submit them separately and in parallel. > A define has been created to make it easy to change its value from a > single location. > > Signed-off-by: Olivier Langlois > --- > fs/io_uring.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/fs/io_uring.c b/fs/io_uring.c > index 02f789e07d4c..3f271bd7726b 100644 > --- a/fs/io_uring.c > +++ b/fs/io_uring.c > @@ -89,6 +89,7 @@ > > #define IORING_MAX_ENTRIES 32768 > #define IORING_MAX_CQ_ENTRIES (2 * IORING_MAX_ENTRIES) > +#define IORING_SQPOLL_CAP_ENTRIES_VALUE 8 > > /* > * Shift of 9 is 512 entries, or exactly one page on 64-bit archs > @@ -6797,8 +6798,8 @@ static int __io_sq_thread(struct io_ring_ctx *ctx, bool cap_entries) > > to_submit = io_sqring_entries(ctx); > /* if we're handling multiple rings, cap submit size for fairness */ > - if (cap_entries && to_submit > 8) > - to_submit = 8; > + if (cap_entries && to_submit > IORING_SQPOLL_CAP_ENTRIES_VALUE) > + to_submit = IORING_SQPOLL_CAP_ENTRIES_VALUE; > > if (!list_empty(&ctx->iopoll_list) || to_submit) { > unsigned nr_events = 0; > -- Pavel Begunkov