On Tue, 30 Aug 2016 11:09:15 +0800 Aaron Lu <[email protected]> wrote:
> >> Case used for test on Haswell EP: > >> usemem -n 72 --readonly -j 0x200000 100G > >> Which spawns 72 processes and each will mmap 100G anonymous space and > >> then do read only access to that space sequentially with a step of 2MB. > >> > >> perf report for base commit: > >> 54.03% usemem [kernel.kallsyms] [k] get_huge_zero_page > >> perf report for this commit: > >> 0.11% usemem [kernel.kallsyms] [k] mm_get_huge_zero_page > > > > Does this mean that overall usemem runtime halved? > > Sorry for the confusion, the above line is extracted from perf report. > It shows the percent of CPU cycles executed in a specific function. > > The above two perf lines are used to show get_huge_zero_page doesn't > consume that much CPU cycles after applying the patch. > > > > > Do we have any numbers for something which is more real-wordly? > > Unfortunately, no real world numbers. > > We think the global atomic counter could be an issue for performance > so I'm trying to solve the problem. So, umm, we don't actually know if the patch is useful to anyone? Some more measurements would help things along, please.
