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[88.147.40.42]) by smtp.gmail.com with ESMTPSA id 34sm42104331wre.32.2019.05.22.01.05.47 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 22 May 2019 01:05:48 -0700 (PDT) From: Paolo Valente Message-Id: Content-Type: multipart/signed; boundary="Apple-Mail=_D125924D-1FFE-4DC1-9485-B31EC5A3E5A7"; 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 10:05:46 +0200 In-Reply-To: <0e3fdf31-70d9-26eb-7b42-2795d4b03722@csail.mit.edu> 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=_D125924D-1FFE-4DC1-9485-B31EC5A3E5A7 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=us-ascii > 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 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? Let me know, Paolo > Thank you! >=20 > Regards, > Srivatsa > VMware Photon OS --Apple-Mail=_D125924D-1FFE-4DC1-9485-B31EC5A3E5A7 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+OneZyvO8OAkCLQGo9oMFAlzlAtoACgkQOAkCLQGo 9oMOew//baPEoy03FXyfpwRm+aDYCXZracwMcV8EWCYLxsc9h+OSDu7YSL3VY+ld 2SyrH2br9GjVHPnM218Moh1g2pTGr9C2BtEzWT72DnGFmZqEYFOS3+KJ6D4FEK/l 6qOtaYyYZDABc5D+wW1B+wouBFeDFH/V4QWpIgyAjKPHi+rTeerEFNzNmsx2SngT mn+AG8kUfecpNhThxEEJxPZN0Edso3t6vet2vsJ7FEmpxD+AW4V6h5oxRBMMlzks JeDs0/gvOV0wiRSAwlmQSecNSssSLLSeouHlLu3+ara3YxdNstDjBd7ODXiabUdX 4NPn9U5baJ8XsC4s6ukMOm1Bc7Q97ZFS4cM5b9FoqTYgWuwL32vbHFPffe/0Ld2g hJcXoI7HmDyGvH4jAvlSQ4hDDkuLRjf0450Y75onK8uq/g6r0VhGXgntHl+ghMvI ykkrXo8cPp9Ii4MiOAbH4FaVj1/1yinJdiIbR7bCdj3kODB8wzLunSAB3GDVTqYr qqFfl6MYNxJi6mUpERhdFa8JsohkU9f/PK+hYh4HYjZNveV1YcSJfcuoCu2t1/yA 04KNr+WG1JFQrrXe+iqXtu5EMD/K6QlH9iBXabq8V/JJ1TR/X3WXo2iPRhDfpKc7 +kRGBjEtU+WJvdECyd4AfTpVuKBK8tUewLIBr7WchCBggJ/4sFg= =q2Kr -----END PGP SIGNATURE----- --Apple-Mail=_D125924D-1FFE-4DC1-9485-B31EC5A3E5A7--