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=-8.2 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,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 AF41DC2D0C6 for ; Sat, 28 Dec 2019 17:04:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7FDD620838 for ; Sat, 28 Dec 2019 17:04:00 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=kernel-dk.20150623.gappssmtp.com header.i=@kernel-dk.20150623.gappssmtp.com header.b="RnhBqvVT" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726315AbfL1RDw (ORCPT ); Sat, 28 Dec 2019 12:03:52 -0500 Received: from mail-pg1-f196.google.com ([209.85.215.196]:35841 "EHLO mail-pg1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726088AbfL1RDv (ORCPT ); Sat, 28 Dec 2019 12:03:51 -0500 Received: by mail-pg1-f196.google.com with SMTP id k3so15979808pgc.3 for ; Sat, 28 Dec 2019 09:03:51 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=subject:to:references:from:message-id:date:user-agent:mime-version :in-reply-to:content-language:content-transfer-encoding; bh=QvjnXLLKPymtY82PWmMDmpJTxCRz0c5SPqFwNtPtmKU=; b=RnhBqvVTxwPcme8Mt7R4p0ZWdzW/udQmCnBzVF8JYnzb0w3T9Jsb1TFegu3VV26cte N7r7CdxxkT2AkfjUud6L8ihKvUckQhQnCjQD1s/gMYZCvXBTV/FPi9uxsBCBCfoYqn4y cwCWY9kO8vQO/iKiOprNvkzSkR6UshOmoJljwM191mkH5JLvu97EEPagEOV+jh88eZXK HpocQZJZ69UAOXqWtoVY5sbBy5glRMSioMaubRtF4WnJwQaeKWu4kkbyo9TgaXJjcSZ4 yu2G4ulDNWQXvQyilN2wR50EB1CfGwBPhcK5EcmEqylOGYLq0e7+G2j8fGfacuGb2s3B m6Sg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=QvjnXLLKPymtY82PWmMDmpJTxCRz0c5SPqFwNtPtmKU=; b=nNcVbg8YD2ndHZAWiBB8dWmDrGWFzDE1Pd74KnIjXAWebmtQOx2yBKgvL2SYQuX+Ly HPYgK+q+IMRKA/yVseZTy5pmsq7ta5nHRB9IVLTFeXJq2PGJvbhFb+4YIN6OiORNmozR XBUI0cGqQ/VWub0wb4bzY54y3pIo2acl6Ikk0DXE4mqHlMLL1kW1S6AxoUhA+rySeKjL jtpXF2lqHZ0O8zVr+dcuRNvZcTFaTsD1gO/c5zicm0dZg8M8M3YUvuxGco2fT3U+37RO iAGe+3vh0m9AW4bIqSxyWodurKtG1nPiYsA3G1JofCkCrAv0Xcu4hE4mMpIIFd/bl8yC vujg== X-Gm-Message-State: APjAAAVJaAvGwQJU4E0hSzMZubGeLv+18RQmMXN/m/+TF/rsBLiPfwTv nUeEdZL91bwPV4fdejUj9BrEet8M7s26IA== X-Google-Smtp-Source: APXvYqwufA27RzTNs7e/EWFqvNItAe3UUyNgAbJ9Ss5Gvs7SJnOUnPZRTUKzb5EpBnlIv2QR6MmxqQ== X-Received: by 2002:aa7:86c3:: with SMTP id h3mr51819095pfo.225.1577552630847; Sat, 28 Dec 2019 09:03:50 -0800 (PST) Received: from [192.168.1.188] ([66.219.217.145]) by smtp.gmail.com with ESMTPSA id t137sm41259142pgb.40.2019.12.28.09.03.49 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sat, 28 Dec 2019 09:03:50 -0800 (PST) Subject: Re: [PATCH v4 2/2] io_uring: batch getting pcpu references To: Pavel Begunkov , io-uring@vger.kernel.org, linux-kernel@vger.kernel.org References: <1250dad37e9b73d39066a8b464f6d2cab26eef8a.1577528535.git.asml.silence@gmail.com> <6facf552-924f-2af1-03e5-99957a90bfd0@gmail.com> From: Jens Axboe Message-ID: Date: Sat, 28 Dec 2019 10:03:49 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.2.2 MIME-Version: 1.0 In-Reply-To: <6facf552-924f-2af1-03e5-99957a90bfd0@gmail.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/28/19 4:15 AM, Pavel Begunkov wrote: > On 28/12/2019 14:13, Pavel Begunkov wrote: >> percpu_ref_tryget() has its own overhead. Instead getting a reference >> for each request, grab a bunch once per io_submit_sqes(). >> >> ~5% throughput boost for a "submit and wait 128 nops" benchmark. >> >> Signed-off-by: Pavel Begunkov >> --- >> fs/io_uring.c | 26 +++++++++++++++++--------- >> 1 file changed, 17 insertions(+), 9 deletions(-) >> >> diff --git a/fs/io_uring.c b/fs/io_uring.c >> index 7fc1158bf9a4..404946080e86 100644 >> --- a/fs/io_uring.c >> +++ b/fs/io_uring.c >> @@ -1080,9 +1080,6 @@ static struct io_kiocb *io_get_req(struct io_ring_ctx *ctx, >> gfp_t gfp = GFP_KERNEL | __GFP_NOWARN; >> struct io_kiocb *req; >> >> - if (!percpu_ref_tryget(&ctx->refs)) >> - return NULL; >> - >> if (!state) { >> req = kmem_cache_alloc(req_cachep, gfp); >> if (unlikely(!req)) >> @@ -1141,6 +1138,14 @@ static void io_free_req_many(struct io_ring_ctx *ctx, void **reqs, int *nr) >> } >> } >> >> +static void __io_req_free_empty(struct io_kiocb *req) > > If anybody have better naming (or a better approach at all), I'm all ears. __io_req_do_free()? I think that's better than the empty, not quite sure what that means. If you're fine with that, I can just make that edit when applying. The rest looks fine to me now. -- Jens Axboe