On Fri, 2012-04-13 at 14:37 -0400, Ted Ts'o wrote: > On Fri, Apr 13, 2012 at 11:31:16AM -0700, Tim Chen wrote: > > > > 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. > > OK, so this is with an 80 CPU machine? > > And when you say 20% speed up, do you mean to say we are actually > being CPU constrained when reading from files on a normal hard disk? > The files are sparse files. So the amount of IO is limited and we are not IO constrained. 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
