On Thu, 13 Oct 2011 10:54:30 -0500 (CDT) Christoph Lameter <cl@xxxxxxxxxx> wrote: > On Thu, 13 Oct 2011, Dimitri Sivanich wrote: > > > > increase the allowed delta per zone if frequent updates occur via the > > > overflow checks in vmstat.c. See calculate_*_threshold there. > > > > I tried changing the threshold in both directions, with slower throughput in > > both cases. > > If that is the case check for the vm_stat cacheline being shared with > another hot kernel variable variable. Maybe that causes cacheline > eviction. yup. `nm -n vmlinux'. > If there are no updates occurring for a while (due to increased deltas > and/or vmstat updates) then the vm_stat cacheline should be able to stay > in shared mode in multiple processors and the performance should increase. > We could cacheline align vm_stat[]. But the thing is pretty small - we couild put each entry in its own cacheline. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>