Re: [PATCH 2/2] alloc_tag: skip pgalloc_tag_swap if profiling is disabled

[Andrew Morton]

On Tue, 14 Jan 2025 08:38:37 -0800 Suren Baghdasaryan <surenb@xxxxxxxxxx> wrote:

> > > Well, a 50% reduction in a 0.0000000001% overhead ain't much.
> >
> > I wish the overhead was that low :)
> >
> > I ran more comprehensive testing on Pixel 6 on Big, Medium and Little cores:
> >
> >                  Overhead before fixes            Overhead after fixes
> >                  slab alloc      page alloc          slab alloc      page alloc
> > Big               6.21%           5.32%                3.31%          4.93%
> > Medium       4.51%           5.05%                3.79%          4.39%
> > Little            7.62%           1.82%                6.68%          1.02%
> 
> Hi Andrew,
> I just noticed that you added the above results to the description of
> this patch in mm-unstable: 366507569511 ("alloc_tag: skip
> pgalloc_tag_swap if profiling is disabled") but this improvement is
> mostly caused the the other patch in this series: 80aded2b9492
> ("alloc_tag: avoid current->alloc_tag manipulations when profiling is
> disabled"). If this is not too much trouble, could you please move it
> into the description of the latter patch?

No probs, done, thanks.