Messages in this thread | | | Date | Mon, 14 Dec 2015 17:56:14 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCHSET 00/16] perf top: Add multi-thread support (v1) |
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On Tue, Dec 15, 2015 at 01:38:30AM +0900, Namhyung Kim wrote: > It requires many changes, but basically I also like the split-up since > it's easier to deal with. IIRC there was an opinion (Andi?) regarding > single-file vs multi-file. The file access will be better for single > file so I changed my earlier implementation to use indexed single data > file instead of multiple files.
The page-cache has a lock per inode, so by having all CPUs populate the one file you get contention on that.
Also, I suppose you'll have to arbitrate ranges in that file for each cpu to make it work, that too could get you some contention.
Having a file per cpu avoids all that.
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