From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752121AbbGOLq6 (ORCPT ); Wed, 15 Jul 2015 07:46:58 -0400 Received: from mail-ie0-f176.google.com ([209.85.223.176]:36059 "EHLO mail-ie0-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750772AbbGOLq5 (ORCPT ); Wed, 15 Jul 2015 07:46:57 -0400 Message-ID: <55A64828.6030007@gmail.com> Date: Wed, 15 Jul 2015 07:46:48 -0400 From: Austin S Hemmelgarn User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 MIME-Version: 1.0 To: Jens Axboe , Mike Snitzer CC: linux-kernel@vger.kernel.org, hch@lst.de Subject: Re: [PATCH 3/3] block: by default, limit maximum discard size to 64MB References: <1436899703-31966-1-git-send-email-axboe@fb.com> <1436899703-31966-4-git-send-email-axboe@fb.com> <20150714204419.GA7915@redhat.com> <55A57507.1030302@fb.com> <55A5839F.8060608@fb.com> In-Reply-To: <55A5839F.8060608@fb.com> x-hashcash: 1:21:150715:axboe@fb.com::4cb57719cebf4707984ca7c7146b76d2:9cee808471505862 x-hashcash: 1:21:150715:snitzer@redhat.com::3339872b896f2b8323c9778505da307:69f613fd32ed729e x-hashcash: 1:21:150715:linux-kernel@vger.kernel.org::a655e613313938e52e73d59cf74a9679:66b3781410241bc6 x-hashcash: 1:21:150715:hch@lst.de::9d8aaab984aef4d7411a3d1ffd771615:b93b9d3a9c6e3de8 x-stampprotocols: hashcash:1:17;mbound:0:10:3000:5000 Content-Type: multipart/signed; protocol="application/pkcs7-signature"; micalg=sha1; boundary="------------ms030200090509010001030900" X-Antivirus: avast! (VPS 150715-0, 2015-07-15), Outbound message X-Antivirus-Status: Clean Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This is a cryptographically signed message in MIME format. --------------ms030200090509010001030900 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: quoted-printable On 2015-07-14 17:48, Jens Axboe wrote: > On 07/14/2015 02:45 PM, Jens Axboe wrote: >> On 07/14/2015 02:44 PM, Mike Snitzer wrote: >>> On Tue, Jul 14 2015 at 2:48pm -0400, >>> Jens Axboe wrote: >>> >>>> Lots of devices exhibit very high latencies for big discards, hurtin= g >>>> reads and writes. By default, limit the max discard we will build to= >>>> 64MB. This value has shown good results across a number of devices. >>>> >>>> This will potentially hurt discard throughput, from a provisioning >>>> point of view (when the user does mkfs.xfs, for instance, and mkfs >>>> issues a full device discard). If that becomes an issue, we could >>>> have different behavior for provisioning vs runtime discards. >>>> >>>> Signed-off-by: Jens Axboe >>> >>> Christoph suggested you impose this default for the specific >>> drivers/devices that benefit. I'm not following why imposing a 64MB >>> default is the right thing to do for all devices. >> >> I'd argue that's most of them... But the testing we did was on NVMe. I= >> can limit it to NVMe, no big deal. > > Oh, and LSI flash too, so not just NVMe. > While I don't have time to test it, I have a feeling that such a limit=20 would help with many of the consumer SSD's out there. Secondarily, once = this gets in and discard is fixed for BTRFS, I'll have some performance=20 testing to do WRT dm-thinp. --------------ms030200090509010001030900 Content-Type: application/pkcs7-signature; name="smime.p7s" Content-Transfer-Encoding: base64 Content-Disposition: attachment; filename="smime.p7s" Content-Description: S/MIME Cryptographic Signature MIAGCSqGSIb3DQEHAqCAMIACAQExCzAJBgUrDgMCGgUAMIAGCSqGSIb3DQEHAQAAoIIGuDCC BrQwggScoAMCAQICAxBuVTANBgkqhkiG9w0BAQ0FADB5MRAwDgYDVQQKEwdSb290IENBMR4w HAYDVQQLExVodHRwOi8vd3d3LmNhY2VydC5vcmcxIjAgBgNVBAMTGUNBIENlcnQgU2lnbmlu ZyBBdXRob3JpdHkxITAfBgkqhkiG9w0BCQEWEnN1cHBvcnRAY2FjZXJ0Lm9yZzAeFw0xNTAz MjUxOTM0MzhaFw0xNTA5MjExOTM0MzhaMGMxGDAWBgNVBAMTD0NBY2VydCBXb1QgVXNlcjEj MCEGCSqGSIb3DQEJARYUYWhmZXJyb2luN0BnbWFpbC5jb20xIjAgBgkqhkiG9w0BCQEWE2Fo ZW1tZWxnQG9oaW9ndC5jb20wggIiMA0GCSqGSIb3DQEBAQUAA4ICDwAwggIKAoICAQCdD/zW 2rRAFCLnDfXpWxU1+ODqRVUgzHvrRO7ADUxRo1CBDc3JSX5TIW2OGmQ3DAKGOACp8Z0sgxMc B05tzAZ/M7m4jajVrwwdVCdrwVGxTdAai7Kwg4ZCVfyMVhcwo8R2eW3QahBx34G0RKumK9sZ ZQSQ+zULAzpY6uz7T1sAk/erMoivRXF6u8WvOsLkOD1F/Xyv1ZccSUG5YeDgZgc0nZUBvyIp zXSHjgWerFkrxEM3y2z/Ff3eL1sgGYecV/I1F+I5S01V7Kclt/qRW10c/4JEGRcI1FmrJBPu BtMYPbg/3Y9LZROYN+mVIFxZxOfrmjfFZ96xt/TaMXo8vcEKtWcNEjhGBjEbfMUEm4aq8ygQ 4MuEcpJc8DJCHBkg2KBk13DkbU2qNepTD6Uip1C+g+KMr0nd6KOJqSH27ZuNY4xqV4hIxFHp ex0zY7mq6fV2o6sKBGQzRdI20FDYmNjsLJwjH6qJ8laxFphZnPRpBThmu0AjuBWE72GnI1oA aO+bs92MQGJernt7hByCnDO82W/ykbVz+Ge3Sax8NY0m2Xdvp6WFDY/PjD9CdaJ9nwQGsUSa N54lrZ2qMTeCI9Vauwf6U69BA42xgk65VvxvTNqji+tZ4aZbarZ7el2/QDHOb/rRwlCFplS/ z4l1f1nOrE6bnDl5RBJyW3zi74P6GwIDAQABo4IBWTCCAVUwDAYDVR0TAQH/BAIwADBWBglg hkgBhvhCAQ0ESRZHVG8gZ2V0IHlvdXIgb3duIGNlcnRpZmljYXRlIGZvciBGUkVFIGhlYWQg b3ZlciB0byBodHRwOi8vd3d3LkNBY2VydC5vcmcwDgYDVR0PAQH/BAQDAgOoMEAGA1UdJQQ5 MDcGCCsGAQUFBwMEBggrBgEFBQcDAgYKKwYBBAGCNwoDBAYKKwYBBAGCNwoDAwYJYIZIAYb4 QgQBMDIGCCsGAQUFBwEBBCYwJDAiBggrBgEFBQcwAYYWaHR0cDovL29jc3AuY2FjZXJ0Lm9y ZzAxBgNVHR8EKjAoMCagJKAihiBodHRwOi8vY3JsLmNhY2VydC5vcmcvcmV2b2tlLmNybDA0 BgNVHREELTArgRRhaGZlcnJvaW43QGdtYWlsLmNvbYETYWhlbW1lbGdAb2hpb2d0LmNvbTAN BgkqhkiG9w0BAQ0FAAOCAgEAGvl7xb42JMRH5D/vCIDYvFY3dR2FPd5kmOqpKU/fvQ8ovmJa p5N/FDrsCL+YdslxPY+AAn78PYmL5pFHTdRadT++07DPIMtQyy2qd+XRmz6zP8Il7vGcEDmO WmMLYMq4xV9s/N7t7JJp6ftdIYUcoTVChUgilDaRWMLidtslCdRsBVfUjPb1bF5Ua31diKDP e0M9/e2CU36rbcTtiNCXhptMigzuL3zJXUf2B9jyUV8pnqNEQH36fqJ7YTBLcpq3aYa2XbAH Hgx9GehJBIqwspDmhPCFZ/QmqUXCkt+XfvinQ2NzKR6P3+OdYbwqzVX8BdMeojh7Ig8x/nIx mQ+/ufstL1ZYp0bg13fyK/hPYSIBpayaC76vzWovkIm70DIDRIFLi20p/qTd7rfDYy831Hjm +lDdCECF9bIXEWFk33kA97dgQIMbf5chEmlFg8S0e4iw7LMjvRqMX3eCD8GJ2+oqyZUwzZxy S0Mx+rBld5rrN7LsXwZ671HsGqNeYbYeU25e7t7/Gcc6Bd/kPfA+adEuUGFcvUKH3trDYqNq 6mOkAd8WO/mQadlc3ztS++XDMhmIpfBre9MPAr6usqf+wc+R8Nk9KLK39kEgrqVfzc/fgf8L MaD4rHnusdg4gca6Yi+kNrm99anw7SwaBrBvULYBp7ixNRUhaYiNW4YjTrYxggShMIIEnQIB ATCBgDB5MRAwDgYDVQQKEwdSb290IENBMR4wHAYDVQQLExVodHRwOi8vd3d3LmNhY2VydC5v cmcxIjAgBgNVBAMTGUNBIENlcnQgU2lnbmluZyBBdXRob3JpdHkxITAfBgkqhkiG9w0BCQEW EnN1cHBvcnRAY2FjZXJ0Lm9yZwIDEG5VMAkGBSsOAwIaBQCgggH1MBgGCSqGSIb3DQEJAzEL BgkqhkiG9w0BBwEwHAYJKoZIhvcNAQkFMQ8XDTE1MDcxNTExNDY0OFowIwYJKoZIhvcNAQkE MRYEFLjwz+IF+Dja5Zr6lsEnRluIPtyeMGwGCSqGSIb3DQEJDzFfMF0wCwYJYIZIAWUDBAEq MAsGCWCGSAFlAwQBAjAKBggqhkiG9w0DBzAOBggqhkiG9w0DAgICAIAwDQYIKoZIhvcNAwIC AUAwBwYFKw4DAgcwDQYIKoZIhvcNAwICASgwgZEGCSsGAQQBgjcQBDGBgzCBgDB5MRAwDgYD VQQKEwdSb290IENBMR4wHAYDVQQLExVodHRwOi8vd3d3LmNhY2VydC5vcmcxIjAgBgNVBAMT GUNBIENlcnQgU2lnbmluZyBBdXRob3JpdHkxITAfBgkqhkiG9w0BCQEWEnN1cHBvcnRAY2Fj ZXJ0Lm9yZwIDEG5VMIGTBgsqhkiG9w0BCRACCzGBg6CBgDB5MRAwDgYDVQQKEwdSb290IENB MR4wHAYDVQQLExVodHRwOi8vd3d3LmNhY2VydC5vcmcxIjAgBgNVBAMTGUNBIENlcnQgU2ln bmluZyBBdXRob3JpdHkxITAfBgkqhkiG9w0BCQEWEnN1cHBvcnRAY2FjZXJ0Lm9yZwIDEG5V MA0GCSqGSIb3DQEBAQUABIICADRN2wuIQxJdwct2NFKtV7wDWjSgBOvQoFDhN82hTb9G9Zbv H6PNLSorqK/6/4QE1zyC/RCuef2PB3osdBTEGq8gzbDFJDsM4Qb7ho/qxxN/bKBtCF6UcblX 01iTrOa47yqrPy1/X6iRrfu1UB3CI117ELdY3mQYrFgumCo4DcOEULBLNxCGiuIs3tfdPVcG 5kSODLbVuC8ySCK203zas/t1+0W4NnY9iUdq8VpJdGTW023mOvmiVDeb5sna/vejGES2tZjH luurS+uTBHVYB/6HGZZN4SQzwGfEKpD4D7ajbvRKialhThuOb63AOwRyB+Rv11qeYOHEInoJ WEC6HbeiNELhsyGXY53aOcO45aLalcs9ge9MTL/2DaNqGSn8Yo+8KnkPBVMhIIKuG4cR6w0s kN+RCNbTSx7QiJD2jJ4xtiS3g3bXoknytlNzyNgDdOd+uNGSVHqFE13/s2gTecrG8w6oRMzO eZzD+yHLhkAplgo0edyVwukhchnJKUUvq36gJvKNLGtcqLysFpwOXkcbSQO1XHu0y3goEArO hcDWSJhTAbnzW7abCXUPctBV1OeaqYwVK9vEwBvYBz9orJJkt+TEkDcVd9/qrIFYoyAzFZ+3 qGeN2JGY7DNnJv7Z6fzqjoBSMTBPJ3TT0wRSncJiYULyh5BUOSRk6oRGQ6fcAAAAAAAA --------------ms030200090509010001030900--