On Wed 10-07-13 18:55:33, Joonsoo Kim wrote: > On Wed, Jul 10, 2013 at 11:17:03AM +0200, Michal Hocko wrote: > > On Wed 10-07-13 09:31:42, Joonsoo Kim wrote: > > > On Thu, Jul 04, 2013 at 12:00:44PM +0200, Michal Hocko wrote: [...] > > > > Which benchmark you are using for this testing? > > > > > > I use my own module which do allocation repeatedly. > > > > I am not sure this microbenchmark will tell us much. Allocations are > > usually not short lived so the longer time might get amortized. > > If you want to use the multi page allocation for read ahead then try to > > model your numbers on read-ahead workloads. > > Of couse. In later, I will get the result on read-ahead workloads or > vmalloc workload which is recommended by Zhang. > > I think, without this microbenchmark, we cannot know this modification's > performance effect to single page allocation accurately. Because the impact > to single page allocation is relatively small and it is easily hidden by > other factors.
The main thing is whether the numbers you get from an artificial microbenchmark matter at all. You might see a regression which cannot be hit in practice because other effects are of magnitude more significant. -- Michal Hocko SUSE Labs -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
