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Groups > linux.kernel > #1412422
| From | Al Viro <viro@ZenIV.linux.org.uk> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [LKP] [lkp] [dcache_{readdir, dir_lseek}() users] 4e82901cd6: reaim.jobs_per_min -49.1% regression |
| Date | 2016-06-02 18:40 +0200 |
| Message-ID | <rFDP3-8ex-13@gated-at.bofh.it> (permalink) |
| References | <rEN46-b2-13@gated-at.bofh.it> <rESds-3nT-13@gated-at.bofh.it> <rF2Pv-1CU-1@gated-at.bofh.it> <rFuiK-2lh-25@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Thu, Jun 02, 2016 at 02:28:36PM +0800, Huang, Ying wrote: > "Huang, Ying" <ying.huang@intel.com> writes: > Here is the comparison result with perf profile information. You can > find it via searching 'perf-profile'. [snip] Looks like this load is hitting the arseloads of contention cases of spin_lock() on various ->d_lock inside dcache_readdir(). With exclusive lock on directory most of them end up uncontended... I'll try to see what can be done there; quite a bit of those are actually due to moving the cursor on every step. I wonder if we could do the list traversals with something less drastic - the real contents changes are prevented by the shared lock on directory being held, after all... I'll play with that and post when I get somewhere with it...
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Re: [lkp] [dcache_{readdir,dir_lseek}() users] 4e82901cd6: reaim.jobs_per_min -49.1% regression Al Viro <viro@ZenIV.linux.org.uk> - 2016-05-31 15:50 +0200
Re: [LKP] [lkp] [dcache_{readdir, dir_lseek}() users] 4e82901cd6: reaim.jobs_per_min -49.1% regression "Huang\, Ying" <ying.huang@intel.com> - 2016-06-01 03:10 +0200
Re: [LKP] [lkp] [dcache_{readdir, dir_lseek}() users] 4e82901cd6: reaim.jobs_per_min -49.1% regression "Huang\, Ying" <ying.huang@intel.com> - 2016-06-02 08:30 +0200
Re: [LKP] [lkp] [dcache_{readdir, dir_lseek}() users] 4e82901cd6: reaim.jobs_per_min -49.1% regression Al Viro <viro@ZenIV.linux.org.uk> - 2016-06-02 18:40 +0200
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