On Thu, Aug 19, 2021 at 12:31 PM Tyler Hicks <tyhicks@xxxxxxxxxxxxxxxxxxx> wrote: > > On 2021-08-19 21:33:43, Zhansaya Bagdauletkyzy wrote: > > Since merged pages are copied every time they need to be modified, > > the write access time is different between shared and non-shared pages. > > Add ksm_cow_time() function which evaluates latency of these COW > > breaks. First, 4000 pages are allocated and the time, required to modify > > 1 byte in every other page, is measured. After this, the pages are > > merged into 2000 pairs and in each pair, 1 page is modified (i.e. they > > are decoupled) to detect COW breaks. The time needed to break COW of > > merged pages is then compared with performance of non-shared pages. > > > > The test is run as follows: ./ksm_tests -C > > The output: > > Total size: 15 MiB > > > > Not merged pages: > > Total time: 0.002185489 s > > Average speed: 3202.945 MiB/s > > > > Merged pages: > > Total time: 0.004386872 s > > Average speed: 1595.670 MiB/s > > > > Signed-off-by: Zhansaya Bagdauletkyzy <zhansayabagdaulet@xxxxxxxxx> > > --- > > v2 -> v3: > > - address Tyler's feedback > > Thanks for incorporating my suggestions! I can confirm that my feedback > was completely addressed. > > Reviewed-by: Tyler Hicks <tyhicks@xxxxxxxxxxxxxxxxxxx> > > Tyler Reviewed-by: Pavel Tatashin <pasha.tatashin@xxxxxxxxxx>
