lkml.org 
[lkml]   [2021]   [Aug]   [20]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRe: [PATCH v3 2/2] selftests: vm: add COW time test for KSM pages
On Thu, Aug 19, 2021 at 12:31 PM Tyler Hicks
<tyhicks@linux.microsoft.com> 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@gmail.com>
> > ---
> > 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@linux.microsoft.com>
>
> Tyler

Reviewed-by: Pavel Tatashin <pasha.tatashin@soleen.com>

\
 
 \ /
  Last update: 2021-08-20 19:20    [W:0.076 / U:0.244 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site