Re: [PATCH v3 0/5] mm/memcg: Reduce kmemcache memory accounting overhead

[Waiman Long]

On 4/15/21 1:10 PM, Matthew Wilcox wrote:
> On Tue, Apr 13, 2021 at 09:20:22PM -0400, Waiman Long wrote:
> > With memory accounting disable, the run time was 2.848s. With memory
> > accounting enabled, the run times with the application of various
> > patches in the patchset were:
> >
> >    Applied patches   Run time   Accounting overhead   Overhead %age
> >    ---------------   --------   -------------------   -------------
> >         None          10.800s         7.952s              100.0%
> >          1-2           9.140s         6.292s               79.1%
> >          1-3           7.641s         4.793s               60.3%
> >          1-5           6.801s         3.953s               49.7%
> I think this is a misleading way to report the overhead.  I would have said:
>
> 			10.800s		7.952s		279.2%
> 			 9.140s		6.292s		220.9%
> 			 7.641s		4.793s		168.3%
> 			 6.801s		3.953s		138.8%
What I want to emphasize is the reduction in the accounting overhead 
part of execution time. Your percentage used the accounting disable time 
as the denominator. I think both are valid, I will be more clear about 
that in my version of the patch.

Thanks,
Longman