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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 1B18CC433F5 for ; Sat, 18 Sep 2021 10:58:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E543660F9C for ; Sat, 18 Sep 2021 10:58:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236353AbhIRLAD (ORCPT ); Sat, 18 Sep 2021 07:00:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55186 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230388AbhIRLAC (ORCPT ); Sat, 18 Sep 2021 07:00:02 -0400 Received: from mail-wm1-x331.google.com (mail-wm1-x331.google.com [IPv6:2a00:1450:4864:20::331]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2FF8FC061574 for ; Sat, 18 Sep 2021 03:58:39 -0700 (PDT) Received: by mail-wm1-x331.google.com with SMTP id b21-20020a1c8015000000b003049690d882so11831356wmd.5 for ; Sat, 18 Sep 2021 03:58:39 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=mime-version:subject:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; bh=vWd1P9CRMg4Pz32pKAdM/AeB1mjDQwEtw2WgM5SSPF4=; b=GxP0VJpMjSAQnSHcRpp4VCpSN/uRrPem/sJhQjSmYVjX2Nw2C/yttldCuXQ+f0ykbE NKHX8rRdL1nNWUItN04YdRX+rBg7bQNJqbz2LXKRwRkSlhJuK8K7J4/52ih6tcghqYMF y0UzTsV/V9sDOmjJatw0QpHA4Xgw6wU4n2G13STe9cLpCXX+ayk9Ezy7UovFQ+brSvfq gNdOpz1gt1CTpmSBiFNNk9P4V2BihgMyJbQ1K3JW0tSyz3A4iCc64KI5kNUpkqzIYjwb sAvDdTV6uk9Q583QFv5d6GR/RQd2ePJ+leMWJeZk648w+jS6YeV1v5+CIm51V7lPanpA AQUg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:subject:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; bh=vWd1P9CRMg4Pz32pKAdM/AeB1mjDQwEtw2WgM5SSPF4=; b=IB6lff4MwvJBVQ6VlN/GKf+x91fLDvoKu0lRZWqIgMsoe4ArWMostGea9hfHHMZyPp T9NC5oiFiDdyMs5dQXvxH8g7y4O5adHX9dsl+k0lA183qbfvte5Z7UGi4pWK9x5mdL5P kh8Ag7YxajNL9JM7MXsKSDGL1gVeF3dx5r35zNrpGAfJOsdKav0P99/6TxAyjhztW2DX AIxX/Zvl/HLQaHSOGivqpUe/hwXtt2Cu9rUkozVZcFG6gw0M4oMJ4Bx4dCAsUn9WuNge wvFI/mGcB/wDAfJp3KyzU9TR1s/zTZdC9rvn2b/vYn6LSd2z/XKXr0nDcYX8kXAIHz/Z 7pWg== X-Gm-Message-State: AOAM533bxceZeqy2WV5AcEuii4kjUma7gSVAyNHLxkoWhsvvuK2it9Lw Rh1YDC99ri17wRjBBRGEMUUnbxrPSxAu8Sbv X-Google-Smtp-Source: ABdhPJxSyiFNq68PRmyizGNSlpPnsbg5rU+WBrY04XMiZa5i2IpyjvwRgxGTN6xkeBABfE2iUk2CWw== X-Received: by 2002:a05:600c:4a16:: with SMTP id c22mr10044589wmp.72.1631962717572; Sat, 18 Sep 2021 03:58:37 -0700 (PDT) Received: from [192.168.136.233] ([37.160.169.152]) by smtp.gmail.com with ESMTPSA id v10sm9858370wri.29.2021.09.18.03.58.36 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Sat, 18 Sep 2021 03:58:37 -0700 (PDT) Content-Type: text/plain; charset=utf-8 Mime-Version: 1.0 (Mac OS X Mail 12.4 \(3445.104.11\)) Subject: Re: [PATCH 0/3 v2] bfq: Limit number of allocated scheduler tags per cgroup From: Paolo Valente In-Reply-To: <20210915131512.GB6166@quack2.suse.cz> Date: Sat, 18 Sep 2021 12:58:34 +0200 Cc: =?utf-8?Q?Michal_Koutn=C3=BD?= , Jens Axboe , linux-block@vger.kernel.org Content-Transfer-Encoding: quoted-printable Message-Id: References: <20210715132047.20874-1-jack@suse.cz> <751F4AB5-1FDF-45B0-88E1-0C76ED1AAAD6@linaro.org> <20210831095930.GB17119@blackbody.suse.cz> <20210915131512.GB6166@quack2.suse.cz> To: Jan Kara X-Mailer: Apple Mail (2.3445.104.11) Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org > Il giorno 15 set 2021, alle ore 15:15, Jan Kara ha = scritto: >=20 > On Tue 31-08-21 11:59:30, Michal Koutn=C3=BD wrote: >> Hello Paolo. >>=20 >> On Fri, Aug 27, 2021 at 12:07:20PM +0200, Paolo Valente = wrote: >>> Before discussing your patches in detail, I need a little help on = this >>> point. You state that the number of scheduler tags must be larger >>> than the number of device tags. So, I expected some of your patches >>> to address somehow this issue, e.g., by increasing the number of >>> scheduler tags. Yet I have not found such a change. Did I miss >>> something? >>=20 >> I believe Jan's conclusions so far are based on "manual" = modifications >> of available scheduler tags by /sys/block/$dev/queue/nr_requests. >> Finding a good default value may be an additional change. >=20 > Exactly. So far I was manually increasing nr_requests. I agree that > improving the default nr_requests value selection would be desirable = as > well so that manual tuning is not needed. But for now I've left that = aside. >=20 Ok. So, IIUC, to recover control on bandwidth you need to (1) increase nr_requests manually and (2) apply your patch If you don't do (1), then (2) is not sufficient, and viceversa. Correct? Thanks, Paolo > Honza > --=20 > Jan Kara > SUSE Labs, CR