Messages in this thread | | | Date | Wed, 29 May 2013 16:37:21 -0400 | From | Waiman Long <> | Subject | Re: [PATCH 0/3 v3] dcache: make it more scalable on large system |
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On 05/29/2013 12:56 PM, Andi Kleen wrote: > On Wed, May 29, 2013 at 12:18:09PM -0400, Simo Sorce wrote: >> To be honest a workload base on /etc/passwd or /etc/group is completely >> artificial, in actual usage, if you really have such access you use >> nscd or sssd with their shared memory caches to completely remove most >> of the file access. > I don't fully agree at this point. A lot of things can be tuned away, > but in practice we want things to perform well out of the box without > needing all kinds of magic tuning that only > > Also this is just normal file access, nothing special about it. > It simply has to scale. For all kinds of workloads. > > And it does, just d_path messes it up.
Just for clarification, the AIM7 workload is not affected by the current d_path() code, they are speed-limited by the lock contention in the dcache reference counting code. However, both the d_path() change and the dentry reference counting change are needed to to eliminate the overhead introduced by the use of the perf-record command.
Regards, Longman
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