Hi, On Mon, 2010-04-19 at 00:14 +0900, Minchan Kim wrote: > On Fri, 2010-04-16 at 15:10 +0100, Steven Whitehouse wrote: > > Hi, > > > > On Fri, 2010-04-16 at 01:51 +0900, Minchan Kim wrote: > > [snip] > > > Thanks for the explanation. It seems to be real issue. > > > > > > I tested to see effect with flush during rb tree search. > > > > > > Before I applied your patch, the time is 50300661 us. > > > After your patch, 11569357 us. > > > After my debug patch, 6104875 us. > > > > > > I tested it as changing threshold value. > > > > > > threshold time > > > 1000 13892809 > > > 500 9062110 > > > 200 6714172 > > > 100 6104875 > > > 50 6758316 > > > > > My results show: > > > > threshold time > > 100000 139309948 > > 1000 13555878 > > 500 10069801 > > 200 7813667 > > 100 18523172 > > 50 18546256 > > > > > And perf shows smp_call_function is very low percentage. > > > > > > In my cases, 100 is best. > > > > > Looks like 200 for me. > > > > I think you meant to use the non _minmax version of proc_dointvec too? > > Yes. My fault :) > > > Although it doesn't make any difference for this basic test. > > > > The original reporter also has 8 cpu cores I've discovered. In his case > > divided by 4 cpus where as mine are divided by 2 cpus, but I think that > > makes no real difference in this case. > > > > I'll try and get some further test results ready shortly. Many thanks > > for all your efforts in tracking this down, > > > > Steve. > > I voted "free area cache". My results with this patch are: vmalloc took 5419238 us vmalloc took 5432874 us vmalloc took 5425568 us vmalloc took 5423867 us So thats about a third of the time it took with my original patch, so very much going in the right direction :-) I did get a compile warning: CC mm/vmalloc.o mm/vmalloc.c: In function ‘__free_vmap_area’: mm/vmalloc.c:454: warning: unused variable ‘prev’ ....harmless, but it should be fixed before the final version, Steve. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>