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Fri, 08 Mar 2019 01:41:53 +0100 Subject: Re: [PATCH v2 0/3] btrfs: trace: Add trace events for extent_io_tree To: dsterba@suse.cz, Qu Wenruo , linux-btrfs@vger.kernel.org References: <20190301024800.17649-1-wqu@suse.com> <20190307163204.GK31119@twin.jikos.cz> From: Qu Wenruo 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: <0adb6db9-db67-05e2-207c-14ca6ea32c64@gmx.com> Date: Fri, 8 Mar 2019 08:41:47 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.5.1 MIME-Version: 1.0 In-Reply-To: <20190307163204.GK31119@twin.jikos.cz> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="vEWZsldA2ewVa9ma7GHGU6XpDHARhkQRD" X-Provags-ID: V03:K1:EHwXajd+lYWdd1fkuMJCw0HIH6ggWDiOdHf9V/Nc6J/Q7x83DyQ o+7irmrR+Qk/aEHr1xqJVDva4FE6jsNu/vaIF4HXIQOswhsjopYjrBB8+tU0EdtUn97PGPp mr1KBZBhhZNEeIbzfRyxaV+AyqYb1/pdKq88mcinHOmYo0X4MeQRkXpG77F+4/64El8xqk5 oDs69kMpo5LQ9Dwh4ZNGw== X-UI-Out-Filterresults: notjunk:1;V03:K0:vIoyIZH3QKM=:7IpnZCD23rwQrc4CKo4cWd aXu2Rd8l+rCKXUDpnOZL4ykVx6kaOf0C4FdIJItYurgkuMRMPsrmGBT8uqRFSjtLeHOt9CYFn cu6ALoTffxkW5qBPQGSQ6hdXFgxCYTniv2yg8/QH/ZWA22hJZJIXBF/K6cpTnS7h1WmLTa7jY PQSMu4ZCtNz36NY+MtkCEHwiM4ot46LkQXTB4seDEK3dSpJCtgtGaHNF0qm+n/DI5gX8xqUio d1+g01tDqXNj41lF8gDeaiMtfx2z8RIx8JNIjM3jA9cKnFs86lKhEJ6xeBzd269kTrqGhzQzw CB0+uUr4Mq4vMtnBh8O0FtwVxtlbP+9lpxx13goWHj1rAIzEODcNe8yjFl1Qk+VhaWmbBljSZ nhOA/n8KAnpwA4YCS1+879kxuYfpDmky3hAAnQRSOu3HClh3xKyx4UEVge7yKLfFvWjAbYve5 q6lAxoHHyXTw6e7vxrmHSe1DXhgfCYtd73NRq/8EjeVy2DbwJw0dEyko5MoeF+ud5iSMMI927 HrzAtj4W1920INHfm+ngye/KFQBjkOjVG2CMRnFiKzMnwxXgK/2wGLr6toCzkfYacj0AApcSo ZXYZ3VsmZuAQkVmEi6sl7T9Ce0fAgAz8czInfMZUGHEWSVB0qRzddiXheZ68wh+6url8zmxiJ maDt8WDr7yu/8hvr11aA4UpBpKTyAG0ihExJErcqb/e5hfLIsh3IkwQWq2gbyEWj+ijKMiUKd MKit/BNJS2q9vshcbJYDKIWrgQ80UfGas/ySa3eJzgCfLc1DCDfHITOrtfmJwK3NNUCKDdSIb DcMz7mssHvnRCeaqZGuSNIe01+bhuO2BouJXmLeLoFiPPwt/frZsnViIgkMCxIT24SnBg34gR PWr8ZJ4K2vMs3NEOZXbCfnTnsAmmPZdsYvQlgbrydQ01jDDkbLmzsY5N8V7dm8 Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --vEWZsldA2ewVa9ma7GHGU6XpDHARhkQRD Content-Type: multipart/mixed; boundary="Q8zCi5E5PgIsKm8HM3v144ntpzW3ZklZy"; protected-headers="v1" From: Qu Wenruo To: dsterba@suse.cz, Qu Wenruo , linux-btrfs@vger.kernel.org Message-ID: <0adb6db9-db67-05e2-207c-14ca6ea32c64@gmx.com> Subject: Re: [PATCH v2 0/3] btrfs: trace: Add trace events for extent_io_tree References: <20190301024800.17649-1-wqu@suse.com> <20190307163204.GK31119@twin.jikos.cz> In-Reply-To: <20190307163204.GK31119@twin.jikos.cz> --Q8zCi5E5PgIsKm8HM3v144ntpzW3ZklZy Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable On 2019/3/8 =E4=B8=8A=E5=8D=8812:32, David Sterba wrote: > On Fri, Mar 01, 2019 at 10:47:57AM +0800, Qu Wenruo wrote: >> - Allow NULL fs_info for TP_fast_assign_fsid() >> There is extent bits operation in selftest which is too deep to pass= >> fs_info. And since it's in selftest, it shouldn't trigger trace >> events. >> But to be safe, we still need to check fs_indo in >> TP_fast_assign_fsid(), for NULL fs_info, just keep fsid filled with >> zero. >=20 > Ok, better be safe here. I'd still like to remove the conditional, as > the tests typically access only a single filesystem we could export the= > fs_info globally, avoiding the need to pass it around. In fact, it's purely to be safe here. Since the selftest is only executed at module load time, it's pretty hard to enable trace event at that small time windows. And if btrfs is complied into kernel, it's definitely impossible. >=20 >> There is one point which need extra attention: >> 1) Those trace events are pretty heavy >> The following workload would generate over 400 trace events. >=20 > I'm not sure if 400 is considered a lot, I'd say 400.000 would be a lot= > for the steps below. Considering other btrfs events are hardly to hit 40 for that small workload, among btrfs specific events, it looks a little heavy. >=20 >> mkfs.btrfs -f $dev >> start_trace >> mount $dev $mnt -o enospc_debug >> sync >> touch $mnt/file1 >> touch $mnt/file2 >> touch $mnt/file3 >> xfs_io -f -c "pwrite 0 16k" $mnt/file4 >> umount $mnt >> end_trace >> It's not recommended to use them in real world environment. >> >> Changelog: >> v2: >> - Introduce fs_info to distinguish different btrfs filesystems >> - Code style change to make trace code more elegant >> - Minor IO_TREE_* naming change. >> - Use btrfs_ino() to replace raw inode number. >> - Change extent_io_tree::owner declaration to avoid affecting spinlock= =2E >=20 > v2 looks good to me, thanks. I'll add it to the 5.2 queue. >=20 Thanks for merging and update it for the renaming. Thanks, Qu --Q8zCi5E5PgIsKm8HM3v144ntpzW3ZklZy-- --vEWZsldA2ewVa9ma7GHGU6XpDHARhkQRD Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEELd9y5aWlW6idqkLhwj2R86El/qgFAlyBukwACgkQwj2R86El /qh9fAf8D9kOzISFkYmjZi/DRLHqeaN1AhGLP9t1KL0vNhb2OKB9APJrcm7aXt0K 5B0+1iCuq9D+cG+Xt4YerF5M3dBeXG7iCNfzABUFv+3q7i/3+Ha2VQlZC5JOcQ4W NFAfJL5I3mgeiOETU/xQkBtYG1DQcwrxpyicML1K8o2G/wmwyohWeG06PC4Dj6GR W926BrZ7QL/h9Bag78fH/VEoT3u9Sf1U9UvB6JdFL3cAgOvdj7XWFxLWcoI9VGsX vDcpxEQUQkycxrab0KWUdfMFQAB0Tsg/aralD5tuDV619pnXsngG3MffOpBvEfBe t5yU3jNNOWf9966QCQTI4BgWbWi+zw== =HjR/ -----END PGP SIGNATURE----- --vEWZsldA2ewVa9ma7GHGU6XpDHARhkQRD--