On Fri, 2012-04-13 at 11:08 -0700, Linus Torvalds wrote: > On Fri, Apr 13, 2012 at 10:53 AM, Tim Chen <tim.c.chen@xxxxxxxxxxxxxxx> wrote: > >> > >> Do you have numbers? > > > > In a benchmark that does mmaped-read, there is a 28% speed up > > after getting rid of the counters. > > Ok, that's big. But is it any actual real workload on a real > filesystem? It looks like this should only happen for actual IO, so I > get the feeling that this is some made-up benchmark for a filesystem > on a RAM-disk? > > Linus Benchmark is working on files on normal hard disk. However, I have I have a large number of processes (80 processes, one for each cpu), each reading a separate mmaped file. The files are in the same directory. That makes cache line bouncing on the counters particularly bad due to the large number of processes running. Tim -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
