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[88.147.71.233]) by smtp.gmail.com with ESMTPSA id z14sm3164273wre.96.2019.06.12.22.46.14 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 12 Jun 2019 22:46:16 -0700 (PDT) From: Paolo Valente Message-Id: <43486E4F-2237-4E40-BDFE-07CFCCFFFA25@linaro.org> Content-Type: multipart/signed; boundary="Apple-Mail=_C82715EC-E52D-48BB-975D-458C5D643A93"; 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: Thu, 13 Jun 2019 07:46:12 +0200 In-Reply-To: <7c5e9d11-4a3d-7df4-c1e6-7c95919522ab@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 , Jeff Moyer , Theodore Ts'o , amakhalov@vmware.com, anishs@vmware.com, srivatsab@vmware.com, Ulf Hansson , Linus Walleij To: "Srivatsa S. Bhat" References: <8d72fcf7-bbb4-2965-1a06-e9fc177a8938@csail.mit.edu> <5B6570A2-541A-4CF8-98E0-979EA6E3717D@linaro.org> <2CB39B34-21EE-4A95-A073-8633CF2D187C@linaro.org> <0e3fdf31-70d9-26eb-7b42-2795d4b03722@csail.mit.edu> <686D6469-9DE7-4738-B92A-002144C3E63E@linaro.org> <01d55216-5718-767a-e1e6-aadc67b632f4@csail.mit.edu> <6FE0A98F-1E3D-4EF6-8B38-2C85741924A4@linaro.org> <2A58C239-EF3F-422B-8D87-E7A3B500C57C@linaro.org> <5b71028c-72f0-73dd-0cd5-f28ff298a0a3@csail.mit.edu> <0d6e3c02-1952-2177-02d7-10ebeb133940@csail.mit.edu> <7B74A790-BD98-412B-ADAB-3B513FB1944E@linaro.org> <6a6f4aa4-fc95-f132-55b2-224ff52bd2d8@csail.mit.edu> <7c5e9d11-4a3d-7df4-c1e6-7c95919522ab@csail.mit.edu> X-Mailer: Apple Mail (2.3445.104.8) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --Apple-Mail=_C82715EC-E52D-48BB-975D-458C5D643A93 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=us-ascii > Il giorno 12 giu 2019, alle ore 00:34, Srivatsa S. Bhat = ha scritto: >=20 > On 6/2/19 12:04 AM, Srivatsa S. Bhat wrote: >> On 5/30/19 3:45 AM, Paolo Valente wrote: >>>=20 > [...] >>> At any rate, since you pointed out that you are interested in >>> out-of-the-box performance, let me complete the context: in case >>> low_latency is left set, one gets, in return for this 12% loss, >>> a) at least 1000% higher responsiveness, e.g., 1000% lower start-up >>> times of applications under load [1]; >>> b) 500-1000% higher throughput in multi-client server workloads, as = I >>> already pointed out [2]. >>>=20 >>=20 >> I'm very happy that you could solve the problem without having to >> compromise on any of the performance characteristics/features of BFQ! >>=20 >>=20 >>> I'm going to prepare complete patches. In addition, if ok for you, >>> I'll report these results on the bug you created. Then I guess we = can >>> close it. >>>=20 >>=20 >> Sounds great! >>=20 >=20 > Hi Paolo, >=20 Hi > Hope you are doing great! >=20 Sort of, thanks :) > I was wondering if you got a chance to post these patches to LKML for > review and inclusion... (No hurry, of course!) >=20 I'm having troubles testing these new patches on 5.2-rc4. As it happened with the first release candidates for 5.1, the CPU of my test machine (Intel Core i7-2760QM@2.40GHz) is so slowed down that results are heavily distorted with every I/O scheduler. Unfortunately, I'm not competent enough to spot the cause of this regression in a feasible amount of time. I hope it'll go away with next release candidates, or I'll test on 5.1. > Also, since your fixes address the performance issues in BFQ, do you > have any thoughts on whether they can be adapted to CFQ as well, to > benefit the older stable kernels that still support CFQ? >=20 I have implanted my fixes on the existing throughput-boosting infrastructure of BFQ. CFQ doesn't have such an infrastructure. If you need I/O control with older kernels, you may want to check my version of BFQ for legacy block, named bfq-sq and available in this repo: https://github.com/Algodev-github/bfq-mq/ I'm willing to provide you with any information or help if needed. Thanks, Paolo > Thank you! >=20 > Regards, > Srivatsa > VMware Photon OS --Apple-Mail=_C82715EC-E52D-48BB-975D-458C5D643A93 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+OneZyvO8OAkCLQGo9oMFAl0B4yQACgkQOAkCLQGo 9oNOVg/+KTDsN0F9V0g74Et2TxDdqnhABWgQ3HrajfUnRzmLdMR0Tx0C0YUBZM5t S3xp4ofC2oP3HItm6gJ+z+Pw/6K+C5k8cd09zRh9W9wkw4dLGXTuotakmMupTpyT XTymYIUfHt72H42arlX0dxtoPkhMMRuP7PXKtvbLun4dLiErjGh03Lvs139EQvyJ L65pJTeoIaTT7r+MlblZkmaVRpqG/XF8yRzRNg5/pSbkvPhegZsJC7pMMdjwLsK8 1skizw2Nt1G24RqGSuofRti9lCDPKLSND2t4xBUZ1BWN93f9Nz3Zm8m9ylWiCNGE c0G3RpRTknqxbYtkPUr71MJZ63Hl2d5F/02XUkZGkSo7EtOoMKiKCg6VzzIq24JP gxL/lMoVO27+JM9DWBUBvdWxkOHtvD1JRAaGX9VWqTi7ksUFDlFHOF83Udyj5HBz PJS2TL5dQ+X+l3G7nD3YHJCwSD2+DC1rZPQhj75BGu1CBnGXaEHtEMn3CfmVVQpL H0pVqIyF7lnJJu+vEYuea73RfnfSi4FU+MpFFYFCG6fElqUik9X7IzCQRcB6ianK vqNbdqMwq9BeFgwm3f09fKzc6JdkBu0YApmPJp9mxeYkvQLJYLxGlyYnUU7ottDL 4QlYZevYyTv9G+O8HM/l8PuET7+X66xi8Dlj5oGnURXNmRLh64g= =PUTU -----END PGP SIGNATURE----- --Apple-Mail=_C82715EC-E52D-48BB-975D-458C5D643A93--