On Tue, Oct 16, 2018 at 06:54:04AM -0700, Matthew Wilcox wrote: >On Tue, Oct 16, 2018 at 09:47:12PM +0800, Wei Yang wrote: >> Based on my understanding, this change would put more accurate vma entry in the >> cache, which means reduce unnecessary vmacache update and vmacache find. >> >> But the test result is not as expected. From the original changelog, I don't >> see the explanation to add this non-overlap entry into the vmacache, so >> curious about why this performs a little better than putting an overlapped >> entry. > >What makes you think this performs any differently for this test-case? >The numbers all seem to fall within a "reasonable variation" range to me. >You're going to need to do some statistics (with a much larger sample >size) to know whether there's any difference at all. > Matthew, Thanks for your comment. I use this test-case because I have little experience in performance test and I see the original author lists the hit-rate improvement in kernel build test. I am thinking to evaluate the cache hit-rate, while I don't know how to gather the statistic. If you could give me some hint on the statistics gathering or a more proper test case, I would appreciate a lot. BTW, I don't get your point on "a much larger sample size". To map a larger memory area? I lost at this point. -- Wei Yang Help you, Help me
