On Mon, Dec 14, 2015 at 05:56:14PM +0100, Peter Zijlstra wrote: > 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.
Right. Now I recall that it was about *report* (not record) time accessing single file vs. multi files. At record time we should use file per cpu. I combined them into one with index at post-processing time in my earlier work. Thanks for clarification! Namhyung -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
