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[88.147.40.42]) by smtp.gmail.com with ESMTPSA id w3sm11277147wrv.25.2019.05.22.02.12.55 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 22 May 2019 02:12:56 -0700 (PDT) From: Paolo Valente Message-Id: <9E95BE27-2167-430F-9C7F-6D4A0E255FF3@linaro.org> Content-Type: multipart/signed; boundary="Apple-Mail=_4DC1C4F9-FFD5-4309-8346-630474A6C16C"; protocol="application/pgp-signature"; micalg=pgp-sha256 Mime-Version: 1.0 (Mac OS X Mail 12.4 \(3445.104.8\)) Subject: Re: CFQ idling kills I/O performance on ext4 with blkio cgroup controller Date: Wed, 22 May 2019 11:12:55 +0200 In-Reply-To: Cc: linux-fsdevel@vger.kernel.org, linux-block , linux-ext4@vger.kernel.org, cgroups@vger.kernel.org, kernel list , Jens Axboe , Jan Kara , jmoyer@redhat.com, Theodore Ts'o , amakhalov@vmware.com, anishs@vmware.com, srivatsab@vmware.com To: "Srivatsa S. Bhat" References: <8d72fcf7-bbb4-2965-1a06-e9fc177a8938@csail.mit.edu> <1812E450-14EF-4D5A-8F31-668499E13652@linaro.org> <46c6a4be-f567-3621-2e16-0e341762b828@csail.mit.edu> <07D11833-8285-49C2-943D-E4C1D23E8859@linaro.org> <5B6570A2-541A-4CF8-98E0-979EA6E3717D@linaro.org> <2CB39B34-21EE-4A95-A073-8633CF2D187C@linaro.org> <0e3fdf31-70d9-26eb-7b42-2795d4b03722@csail.mit.edu> X-Mailer: Apple Mail (2.3445.104.8) Sender: linux-ext4-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org --Apple-Mail=_4DC1C4F9-FFD5-4309-8346-630474A6C16C Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=us-ascii > Il giorno 22 mag 2019, alle ore 11:02, Srivatsa S. Bhat = ha scritto: >=20 > On 5/22/19 1:05 AM, Paolo Valente wrote: >>=20 >>=20 >>> Il giorno 22 mag 2019, alle ore 00:51, Srivatsa S. Bhat = ha scritto: >>>=20 >>> [ Resending this mail with a dropbox link to the traces (instead >>> of a file attachment), since it didn't go through the last time. ] >>>=20 >>> On 5/21/19 10:38 AM, Paolo Valente wrote: >>>>=20 >>>>> So, instead of only sending me a trace, could you please: >>>>> 1) apply this new patch on top of the one I attached in my = previous email >>>>> 2) repeat your test and report results >>>>=20 >>>> One last thing (I swear!): as you can see from my script, I tested = the >>>> case low_latency=3D0 so far. So please, for the moment, do your = test >>>> with low_latency=3D0. You find the whole path to this parameter = in, >>>> e.g., my script. >>>>=20 >>> No problem! :) Thank you for sharing patches for me to test! >>>=20 >>> I have good news :) Your patch improves the throughput significantly >>> when low_latency =3D 0. >>>=20 >>> Without any patch: >>>=20 >>> dd if=3D/dev/zero of=3D/root/test.img bs=3D512 count=3D10000 = oflag=3Ddsync >>> 10000+0 records in >>> 10000+0 records out >>> 5120000 bytes (5.1 MB, 4.9 MiB) copied, 58.0915 s, 88.1 kB/s >>>=20 >>>=20 >>> With both patches applied: >>>=20 >>> dd if=3D/dev/zero of=3D/root/test0.img bs=3D512 count=3D10000 = oflag=3Ddsync >>> 10000+0 records in >>> 10000+0 records out >>> 5120000 bytes (5.1 MB, 4.9 MiB) copied, 3.87487 s, 1.3 MB/s >>>=20 >>> The performance is still not as good as mq-deadline (which achieves >>> 1.6 MB/s), but this is a huge improvement for BFQ nonetheless! >>>=20 >>> A tarball with the trace output from the 2 scenarios you requested, >>> one with only the debug patch applied = (trace-bfq-add-logs-and-BUG_ONs), >>> and another with both patches applied (trace-bfq-boost-injection) is >>> available here: >>>=20 >>> https://www.dropbox.com/s/pdf07vi7afido7e/bfq-traces.tar.gz?dl=3D0 >>>=20 >>=20 >> Hi Srivatsa, >> I've seen the bugzilla you've created. I'm a little confused on how >> to better proceed. Shall we move this discussion to the bugzilla, or >> should we continue this discussion here, where it has started, and >> then update the bugzilla? >>=20 >=20 > Let's continue here on LKML itself. Just done :) > The only reason I created the > bugzilla entry is to attach the tarball of the traces, assuming > that it would allow me to upload a 20 MB file (since email attachment > didn't work). But bugzilla's file restriction is much smaller than > that, so it didn't work out either, and I resorted to using dropbox. > So we don't need the bugzilla entry anymore; I might as well close it > to avoid confusion. >=20 No no, don't close it: it can reach people that don't use LKML. We just have to remember to report back at the end of this. BTW, I also think that the bug is incorrectly filed against 5.1, while all these tests and results concern 5.2-rcX. Thanks, Paolo > Regards, > Srivatsa > VMware Photon OS --Apple-Mail=_4DC1C4F9-FFD5-4309-8346-630474A6C16C Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename=signature.asc Content-Type: application/pgp-signature; name=signature.asc Content-Description: Message signed with OpenPGP -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEEpYoduex+OneZyvO8OAkCLQGo9oMFAlzlEpcACgkQOAkCLQGo 9oPdEw//WxVy6NXqpJ3PDhtxBUM+Q1PcVKlaTaCBteRnbxyptYxJJuedsDp9j1O1 yU2XB75LNHy4NFLIVAqvdtSbmGpSl16XgFEq3t4/f5dGd066RhiV8f4APnQuqXHm MlwYjL6BdqYzP7MUCA7xBM0eNztJmHMpisG/ox1fpk4/YrJm0N9y0LHSxazPOaao dsRUqa97+tT3znMqFgTwGkfsYUZcuKc+nyQuZaFUwwKww8SqJYVTSXtcE+BIsngu tyw52Ty26br/9An4BXGXiDOXzB45s+AsvpJK+kntxB9BqSLnvCTNAWqPSJyvoHgn 8DJvTjqHk53JsGuEs0kie3mGVB7VbDQ2ljRYhbYx11pVYKSxvS0ykmMKMd64Vyyb /VbB7q8t3cfpCU1YPsWUPjeiZIBkQNqlYsdhA1AclUMMEAo5k7nVZEG1tlvZrL9t D4sY5nOxd5shFqEb5wwxlMvmoLh7VP3bkxfuDetg/fKBT5HvsNcYrgX7EgumrM7j O+5KsvvhH/JbAXg70sicLqBZZGeXWf9s7lPO3JdVkoTXy2VaaQuFGocTN2tzMYhx 5058wdhCYh8wnEJ3L+13JQv/P88WNiYkCzMJglsp7MKOFGWv7gzcyARTqkuhjm4h x5nNzFvvG6VWQi1LIWCMEthAWWoo+F2QDvHi71g890jQLrE0Ibg= =EX0B -----END PGP SIGNATURE----- --Apple-Mail=_4DC1C4F9-FFD5-4309-8346-630474A6C16C--