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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D09ACC433F5 for ; Tue, 12 Oct 2021 14:57:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B96B461052 for ; Tue, 12 Oct 2021 14:57:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237254AbhJLO7s (ORCPT ); Tue, 12 Oct 2021 10:59:48 -0400 Received: from mail-wr1-f42.google.com ([209.85.221.42]:39776 "EHLO mail-wr1-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237062AbhJLO7r (ORCPT ); Tue, 12 Oct 2021 10:59:47 -0400 Received: by mail-wr1-f42.google.com with SMTP id r18so67903685wrg.6; Tue, 12 Oct 2021 07:57:45 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=VtXwb5BYNS5KGkt6MvcktBG7LF1gDr4C50twzOZ5210=; b=dKrfiLoFLSGrv+exOJ6XTc8x2FJ4nzNfs87PivVDdio8by8PwF2VA2x2wo/aCPm8P8 PZb9sRBYEufUaUQo4ZWQjhsH7pxXvmaqZM43QZij5KBN9iuZzIoNf2qhZRii4aIuLuDE dIpaaPTNXsFHlEgVrN0Mac0LbUwNelAN5L2rBaOrx1yhGZgErce6UwioY065JsHoQvy0 8a1Ro6TgLh5SnRwss3JvwxVopSq1eiA5niM/bdxig2CtPxVSqgTOZmPlMnQKFpVOiC/f 6ZtSc2fXHFqTLkCIRYhyr8MR5FEQhwPka0GSpWAtDg4O3Q55LfRzm8QwdQFj9bYihGrk uk5A== X-Gm-Message-State: AOAM532cRh4mAk8CFELdzkSjZcSESy6HnxoGm5k4E6dmrKO9EQpJLnTH CO3GQLTx+emohBjF4RHB1kY= X-Google-Smtp-Source: ABdhPJxz+cYCges9NE0K4zRRi+5Im04qxitQs7NFCycHffQ+nJC3FVxsi+esTCwTWq5519XTQc7Pqw== X-Received: by 2002:a05:600c:35d0:: with SMTP id r16mr3654310wmq.97.1634050665189; Tue, 12 Oct 2021 07:57:45 -0700 (PDT) Received: from [192.168.81.70] (bzq-219-42-90.isdn.bezeqint.net. [62.219.42.90]) by smtp.gmail.com with ESMTPSA id w2sm5646211wrt.31.2021.10.12.07.57.43 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 12 Oct 2021 07:57:44 -0700 (PDT) Subject: Re: switch block layer polling to a bio based model v4 To: Jens Axboe , Christoph Hellwig Cc: Jeffle Xu , Ming Lei , Damien Le Moal , Keith Busch , "Wunderlich, Mark" , "Vasudevan, Anil" , linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-nvme@lists.infradead.org References: <20211012111226.760968-1-hch@lst.de> <07f31547-5570-4150-7a4b-1d773fb9fa87@kernel.dk> From: Sagi Grimberg Message-ID: <040104f6-720d-35ed-7e15-a704e6488fd4@grimberg.me> Date: Tue, 12 Oct 2021 17:57:43 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.13.0 MIME-Version: 1.0 In-Reply-To: <07f31547-5570-4150-7a4b-1d773fb9fa87@kernel.dk> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org >> Hi all, >> >> This series clean up the block polling code a bit and changes the interface >> to poll for a specific bio instead of a request_queue and cookie pair. >> >> Polling for the bio itself leads to a few advantages: >> >> - the cookie construction can made entirely private in blk-mq.c >> - the caller does not need to remember the request_queue and cookie >> separately and thus sidesteps their lifetime issues >> - keeping the device and the cookie inside the bio allows to trivially >> support polling BIOs remapping by stacking drivers >> - a lot of code to propagate the cookie back up the submission path can >> removed entirely >> >> The one major caveat is that this requires RCU freeing polled BIOs to make >> sure the bio that contains the polling information is still alive when >> io_uring tries to poll it through the iocb. For synchronous polling all the >> callers have a bio reference anyway, so this is not an issue. > > I ran this through the usual peak testing, and it doesn't seem to regress > anything for me. We're still at around ~7.4M polled IOPS on a single CPU > core: > > taskset -c 0,16 t/io_uring -d128 -b512 -s32 -c32 -p1 -F1 -B1 -D1 -n2 /dev/nvme1n1 /dev/nvme2n1 > Added file /dev/nvme1n1 (submitter 0) > Added file /dev/nvme2n1 (submitter 1) > polled=1, fixedbufs=1, register_files=1, buffered=0, QD=128 > Engine=io_uring, sq_ring=128, cq_ring=256 > submitter=0, tid=1199 > submitter=1, tid=1200 > IOPS=7322112, BW=3575MiB/s, IOS/call=32/31, inflight=(110 71) > IOPS=7452736, BW=3639MiB/s, IOS/call=32/31, inflight=(52 80) > IOPS=7419904, BW=3623MiB/s, IOS/call=32/31, inflight=(78 104) > IOPS=7392576, BW=3609MiB/s, IOS/call=32/32, inflight=(75 102) Jens, is that with nvme_core.multipath=Y ?