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=-0.7 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=ham 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 4626CC43381 for ; Sat, 30 Mar 2019 12:31:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0546F2184D for ; Sat, 30 Mar 2019 12:31:20 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=gmx.net header.i=@gmx.net header.b="eLI+reTg" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730645AbfC3MbT (ORCPT ); Sat, 30 Mar 2019 08:31:19 -0400 Received: from mout.gmx.net ([212.227.15.15]:39915 "EHLO mout.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730510AbfC3MbT (ORCPT ); Sat, 30 Mar 2019 08:31:19 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gmx.net; s=badeba3b8450; t=1553949077; bh=9ZHyt3SR+rgdJcF4NsX8GUU3tK45nZVWmsb9fW5V+i0=; h=X-UI-Sender-Class:To:From:Subject:Date; b=eLI+reTgRcmVyvuwqKGz2HIaj5K+VSsKF0kvjNRMKmT5m+8W/2eOSqjW9LNJEL/mW rt1JMehHn24xzvHCMxMV9wokOMnjS/byJha2C/n7quROOYX7zmE+K8cBm00YdRQbOa FmVDqdpK1iYo2D9U6kHuCHaLXl/oFS5251pMgUAk= X-UI-Sender-Class: 01bb95c1-4bf8-414a-932a-4f6e2808ef9c Received: from [0.0.0.0] ([210.140.77.29]) by mail.gmx.com (mrgmx003 [212.227.17.184]) with ESMTPSA (Nemesis) id 0Lpbqo-1gV7kw03pm-00fTBh; Sat, 30 Mar 2019 13:31:17 +0100 To: "linux-btrfs@vger.kernel.org" , Linux FS Devel , linux-block@vger.kernel.org From: Qu Wenruo Subject: Is it possible that certain physical disk doesn't implement flush correctly? Openpgp: preference=signencrypt Autocrypt: addr=quwenruo.btrfs@gmx.com; prefer-encrypt=mutual; keydata= mQENBFnVga8BCACyhFP3ExcTIuB73jDIBA/vSoYcTyysFQzPvez64TUSCv1SgXEByR7fju3o 8RfaWuHCnkkea5luuTZMqfgTXrun2dqNVYDNOV6RIVrc4YuG20yhC1epnV55fJCThqij0MRL 1NxPKXIlEdHvN0Kov3CtWA+R1iNN0RCeVun7rmOrrjBK573aWC5sgP7YsBOLK79H3tmUtz6b 9Imuj0ZyEsa76Xg9PX9Hn2myKj1hfWGS+5og9Va4hrwQC8ipjXik6NKR5GDV+hOZkktU81G5 gkQtGB9jOAYRs86QG/b7PtIlbd3+pppT0gaS+wvwMs8cuNG+Pu6KO1oC4jgdseFLu7NpABEB AAG0IlF1IFdlbnJ1byA8cXV3ZW5ydW8uYnRyZnNAZ214LmNvbT6JAVQEEwEIAD4CGwMFCwkI BwIGFQgJCgsCBBYCAwECHgECF4AWIQQt33LlpaVbqJ2qQuHCPZHzoSX+qAUCWdWCnQUJCWYC bgAKCRDCPZHzoSX+qAR8B/94VAsSNygx1C6dhb1u1Wp1Jr/lfO7QIOK/nf1PF0VpYjTQ2au8 ihf/RApTna31sVjBx3jzlmpy+lDoPdXwbI3Czx1PwDbdhAAjdRbvBmwM6cUWyqD+zjVm4RTG rFTPi3E7828YJ71Vpda2qghOYdnC45xCcjmHh8FwReLzsV2A6FtXsvd87bq6Iw2axOHVUax2 FGSbardMsHrya1dC2jF2R6n0uxaIc1bWGweYsq0LXvLcvjWH+zDgzYCUB0cfb+6Ib/ipSCYp 3i8BevMsTs62MOBmKz7til6Zdz0kkqDdSNOq8LgWGLOwUTqBh71+lqN2XBpTDu1eLZaNbxSI ilaVuQENBFnVga8BCACqU+th4Esy/c8BnvliFAjAfpzhI1wH76FD1MJPmAhA3DnX5JDORcga CbPEwhLj1xlwTgpeT+QfDmGJ5B5BlrrQFZVE1fChEjiJvyiSAO4yQPkrPVYTI7Xj34FnscPj /IrRUUka68MlHxPtFnAHr25VIuOS41lmYKYNwPNLRz9Ik6DmeTG3WJO2BQRNvXA0pXrJH1fN GSsRb+pKEKHKtL1803x71zQxCwLh+zLP1iXHVM5j8gX9zqupigQR/Cel2XPS44zWcDW8r7B0 q1eW4Jrv0x19p4P923voqn+joIAostyNTUjCeSrUdKth9jcdlam9X2DziA/DHDFfS5eq4fEv ABEBAAGJATwEGAEIACYWIQQt33LlpaVbqJ2qQuHCPZHzoSX+qAUCWdWBrwIbDAUJA8JnAAAK CRDCPZHzoSX+qA3xB/4zS8zYh3Cbm3FllKz7+RKBw/ETBibFSKedQkbJzRlZhBc+XRwF61mi f0SXSdqKMbM1a98fEg8H5kV6GTo62BzvynVrf/FyT+zWbIVEuuZttMk2gWLIvbmWNyrQnzPl mnjK4AEvZGIt1pk+3+N/CMEfAZH5Aqnp0PaoytRZ/1vtMXNgMxlfNnb96giC3KMR6U0E+siA 4V7biIoyNoaN33t8m5FwEwd2FQDG9dAXWhG13zcm9gnk63BN3wyCQR+X5+jsfBaS4dvNzvQv h8Uq/YGjCoV1ofKYh3WKMY8avjq25nlrhzD/Nto9jHp8niwr21K//pXVA81R2qaXqGbql+zo Message-ID: Date: Sat, 30 Mar 2019 20:31:08 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.5.3 MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="LgzMUsLborRE8e4cwj4yTVNxGRf2MnYFv" X-Provags-ID: V03:K1:FhiomOT/Crfn+x0qtR8kwWj4qjzIu7Qr/OtN/UW3834YW7ZB1Mn 1QXb4VCAuXHN7WAAfjJpVdhuYQpR3gNXSkV9TYS+NUci5+t9rBrQMgnH1GcvylrYRs/UWWX 3AW6JvOtSAIqyK9YV5WYmNcpKym/0E9n6lSGWEgBvgxQ5JUP2LcvVH9gqlyQVpIZ0xqMfYW bwHH+A8R8jq9dzRBeZooQ== X-UI-Out-Filterresults: notjunk:1;V03:K0:VlS7qES0mkc=:DZOLllc9HVbfBGHd0QhX+m 4zFaNy/nfxnOLNzx3cvIEbt643nmIKRfZynZZFgU2rchh3fvgprbq+gsESrkMvqyDTVeDQ6Gc EBGbMlzq45p+DkirMhn+F/6ySbtJvjNU63QAp0qJ1WN0FKM9CtRCUA+nrCdDlDf/YKPlXWjwZ 6McoiHbQkI8jMQ9SoEVh3oSA+K1fr5+N074UVy2vT//WMl/q5dLhfW6kWxUnn2U0O0SJQof7y TgsUsjUX0kfFJcN1B+FqZ9bicoCsgcMklub8P8nfHBpDOVn6LeGBJsthKZ+CEZDPSGcd4S2Lc Pmboj0B5QysWg80uZD1uCAFm3Xtw3i9U8qzobdGPJmUCdrpQqvhOh2Q/LrB6kbRcYIXDsHnT5 tnsjbeejD+YaAbRjeWthw1qde8YalvQ5B0iHLQ7QxW3uFKqgEjbmyiqPL4JbYQiLZEiQltiCc goteB99lo94lASecSBamWzS+IdWTEwqbGKnEPj1PicZKoXIMHIQ2bgsRy7msmL0UXZh0tbVl4 nYGRVvhDkhXkye2fjEckCe25UTXFv/f5/gPYZYYaXxkz3v54dyQBNFaCefywzVUZpNMyutsTs 6cRKuNPncSERa1lxiCIrLh5Q9ycozuPECx5p/WXNRnOsmAjtGoDOtMclwI4TqDt50c/pJavVx YGr/CdXJhnuUiIMmXZBkJZJWRYQUHtcbcIRmkUNpbrnyfIsJoaWL1VloICt9JP+eEYkr23NPh azCUJTZGV5WNnbuLn87qAGrbVO9LWSQ5PhuPfBif9xLmpKGR1285WBNut7PHG9uduGtEAjqge JxitnU/nMI/jnv0lEFKTdHlXotzLtgyt4Znx/br5ICaMM7fN6cR+GqjREcrEwkOdqr6Phn8tI 7lRS4Tljk/7wrQ+pjesJcNtpOHMuHqQLAM6vCGMvMtAoS1qbXVcHRJzPCA6DdI Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --LgzMUsLborRE8e4cwj4yTVNxGRf2MnYFv Content-Type: multipart/mixed; boundary="lJJTIDHHrLzsySp7feQTJfLGV7wLPCjwN"; protected-headers="v1" From: Qu Wenruo To: "linux-btrfs@vger.kernel.org" , Linux FS Devel , linux-block@vger.kernel.org Message-ID: Subject: Is it possible that certain physical disk doesn't implement flush correctly? --lJJTIDHHrLzsySp7feQTJfLGV7wLPCjwN Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable Hi, I'm wondering if it's possible that certain physical device doesn't handle flush correctly. E.g. some vendor does some complex logical in their hdd controller to skip certain flush request (but not all, obviously) to improve performanc= e? Do anyone see such reports? And if proves to happened before, how do we users detect such problem? Can we just check the flush time against the write before flush call? E.g. write X random blocks into that device, call fsync() on it, check the execution time. Repeat Y times, and compare the avg/std. And change X to 2X/4X/..., repeat above check. Thanks, Qu --lJJTIDHHrLzsySp7feQTJfLGV7wLPCjwN-- --LgzMUsLborRE8e4cwj4yTVNxGRf2MnYFv Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEELd9y5aWlW6idqkLhwj2R86El/qgFAlyfYYwACgkQwj2R86El /qicQAgAkP9/9VhXS899TPfJdRpv0eFR0IGDUQzly5VyqzhwOwR2ejbXUVGaLsU3 3rCv988uZwU634rKyA1PGZs1L7yYY0Cd4hBrK4FMA1x8+TCI7Idc4N5C6Ho5+aCd HoOB5WG/I2nQLv0wglOeKvBPwSsTFmVOoFwTa/UQT/zMaONlhTkNf0FInOB1W8W0 Dl0/k+NModJfXYrLl67SQjDqBsbUlsLtkZBTrPC8rRz8L9J3rOw3pslgQtLhORI2 nAc7b9/+UevL0G2/jh9Lh3JTcAAhLPE8Jv8gFcJ8bP66QycCqtqrQvOCyWxCiHRe 31oahlkJdQ+SpeyOBmonxmkAGEeg8A== =GkOv -----END PGP SIGNATURE----- --LgzMUsLborRE8e4cwj4yTVNxGRf2MnYFv--