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=-10.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, HTML_MESSAGE,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL 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 DAADEC07E95 for ; Tue, 13 Jul 2021 08:15:47 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 7190861003 for ; Tue, 13 Jul 2021 08:15:47 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7190861003 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id A01D66B008C; Tue, 13 Jul 2021 04:15:47 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 98ADD6B0095; Tue, 13 Jul 2021 04:15:47 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 7DC986B0096; Tue, 13 Jul 2021 04:15:47 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0215.hostedemail.com [216.40.44.215]) by kanga.kvack.org (Postfix) with ESMTP id 525156B008C for ; Tue, 13 Jul 2021 04:15:47 -0400 (EDT) Received: from smtpin14.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 4CBF918525742 for ; Tue, 13 Jul 2021 08:15:46 +0000 (UTC) X-FDA: 78356855892.14.2A4B52A Received: from mail-yb1-f179.google.com (mail-yb1-f179.google.com [209.85.219.179]) by imf21.hostedemail.com (Postfix) with ESMTP id EDDDBD0052B4 for ; Tue, 13 Jul 2021 08:15:45 +0000 (UTC) Received: by mail-yb1-f179.google.com with SMTP id a16so33439017ybt.8 for ; Tue, 13 Jul 2021 01:15:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=9qlYEx8s3VeTkLgmc0bQvmD6KtEAlqgVjVc3p35zSVw=; b=HhADCmg4/BKtZble24xKfaY8QebDL5L1Eev924kGl84RdUWwqm4JMzJEZfSoje+stA 7oGjezUgeElDTP4sCJNnVg7XHb3EgM5AAgFGhTnddjA3j6tEQzIXCjqQO5Qlc+accm46 cxWRKuOZxzh1TYbrrseEjn1ArVZhYrWihgCHtZWiFpHcEt6u5Ni5XztaovthW1Ti5eHK bRAU3vxGx1H31PKaPa/hSzcDEoU2r9fRXpBb8YwDeXbc1kqk/tq/O+7EijZYUeGEVwqm wT8FSEn7z6sXy330LvYvZAJe4cJv1++phMWtD0D45C2OtPjfn+K566jTSOb3cJICL3ta B8Qw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=9qlYEx8s3VeTkLgmc0bQvmD6KtEAlqgVjVc3p35zSVw=; b=OrgGZLjeEDY8WqTuMZUo2h5dZo5WDL/pYp80emfG1/GfJZ0A5WDefqLmQCgc3Fe+we 1dc4GlKZfhznCdKPI0NmFgyH9nCI+m1kA5PWZpBsCTO9c8kAHp2gaJFJmr0Mk/HnqZJA goBtRj+FsIUioTOpoBVZzi9IIKYPjYRCXMgTF3p/CJxqtKHrsNLoaIPoxUBj1cMAd34I hpA5PYLmz5Q+jwXt0S+ioTfbj2ne1JswtwigMFmFn11LavA9iATQyFL3CWahHuXhBvQs I80z6vurqxNlhyugpmCuKscRzpnLiIC+geAl2mDbucWwjsvnk4SdVN5yDVa5HkkP/12v YgSg== X-Gm-Message-State: AOAM530VzEPow3fRgVu4zGCkDnVobIdAy8vdStbn78AjwmRdeIT/Rivm 9EI9TI1hrx5wxxcbLFY1CJ6eN+e/bO0FFDJnHkvSrA== X-Google-Smtp-Source: ABdhPJwaEhDi8lIm2okdXoBRR1Isu76k31j2vz736P64j9dmkuxFrMicXgT2JV66cJm30i0e1HRBnDv6WsJcWBDQAFY= X-Received: by 2002:a25:208b:: with SMTP id g133mr4172534ybg.211.1626164145078; Tue, 13 Jul 2021 01:15:45 -0700 (PDT) MIME-Version: 1.0 References: <20210705161610.19406-1-jack@suse.cz> <20210712162733.GB9804@quack2.suse.cz> In-Reply-To: <20210712162733.GB9804@quack2.suse.cz> From: Michael Stapelberg Date: Tue, 13 Jul 2021 10:15:33 +0200 Message-ID: Subject: Re: [PATCH 0/5] writeback: Fix bandwidth estimates To: Jan Kara Cc: Andrew Morton , linux-fsdevel@vger.kernel.org, linux-mm Content-Type: multipart/alternative; boundary="00000000000037200b05c6fcd8a0" X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: EDDDBD0052B4 X-Stat-Signature: 3oyq5zqyhu7gtp7a9j1xbrxftosq9cn4 Authentication-Results: imf21.hostedemail.com; dkim=pass header.d=google.com header.s=20161025 header.b=HhADCmg4; dmarc=pass (policy=reject) header.from=google.com; spf=pass (imf21.hostedemail.com: domain of stapelberg@google.com designates 209.85.219.179 as permitted sender) smtp.mailfrom=stapelberg@google.com X-HE-Tag: 1626164145-189638 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: --00000000000037200b05c6fcd8a0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Yes! Thank you. On Mon, 12 Jul 2021 at 18:27, Jan Kara wrote: > On Fri 09-07-21 15:19:17, Michael Stapelberg wrote: > > Thanks for sending this patch series! > > > > I have used the mmap.c reproducer as before, with the following > parameters: > > * mkdir /tmp/mnt > > * fusermount -u /tmp/mnt; /root/fuse-2.9.9/example/fusexmp_fh -f /tmp/m= nt > > * dd if=3D/dev/urandom of=3D/tmp/was bs=3D1M count=3D99 > > * while :; do grep ^Bdi /sys/kernel/debug/bdi/0:44/stats; sleep 0.1; do= ne > > * while :; do time WORKAROUND=3D1 ~/mmap /tmp/was > > /tmp/mnt/tmp/stapelberg.1; sleep 5; done > > > > Previously, after a few iterations, the BdiWriteBandwidth measure > > would gradually approach 0. > > > > With your patch series applied, the BdiWriteBandwidth is updated much > > more quickly, and converges to =E2=89=8816000 kBps. > > When I start copying more quickly, the bandwidth measure rises quickly. > > > > As far as I understand, this should fix the problem (provided 16000 > > kBps is an okay value). > > Certainly, I don=E2=80=99t see the downward spiral either with your pat= ches :) > > Thanks for testing! Can I add your Tested-by tag? > > Honza > -- > Jan Kara > SUSE Labs, CR > --00000000000037200b05c6fcd8a0 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
Yes! Thank you.

On Mon, 12 Jul 2021 at 18:27, Jan Kara <= jack@suse.cz> wrote:
On Fri 09-07-21 15:19:17, Micha= el Stapelberg wrote:
> Thanks for sending this patch series!
>
> I have used the mmap.c reproducer as before, with the following parame= ters:
> * mkdir /tmp/mnt
> * fusermount -u /tmp/mnt; /root/fuse-2.9.9/example/fusexmp_fh -f /tmp/= mnt
> * dd if=3D/dev/urandom of=3D/tmp/was bs=3D1M count=3D99
> * while :; do grep ^Bdi /sys/kernel/debug/bdi/0:44/stats; sleep 0.1; d= one
> * while :; do time WORKAROUND=3D1 ~/mmap /tmp/was
> /tmp/mnt/tmp/stapelberg.1; sleep 5; done
>
> Previously, after a few iterations, the BdiWriteBandwidth measure
> would gradually approach 0.
>
> With your patch series applied, the BdiWriteBandwidth is updated much<= br> > more quickly, and converges to =E2=89=8816000 kBps.
> When I start copying more quickly, the bandwidth measure rises quickly= .
>
> As far as I understand, this should fix the problem (provided 16000 > kBps is an okay value).
> Certainly, I don=E2=80=99t see the downward spiral either with your pa= tches :)

Thanks for testing! Can I add your Tested-by tag?

=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2= =A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 = =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2= =A0 Honza
--
Jan Kara <jack@suse.c= om>
SUSE Labs, CR
--00000000000037200b05c6fcd8a0--