lkml.org 
[lkml]   [2020]   [Jun]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRe: [gup] 17839856fd: stress-ng.vm-splice.ops_per_sec 2158.6% improvement
On Mon, Jun 15, 2020 at 12:33 AM Jann Horn <jannh@google.com> wrote:
>
> So in summary I guess the test was just really slow up until now
> because it was hitting a slowpath that you wouldn't hit during normal
> usage? At least for vmsplice(), writing uninitialized pages doesn't
> really make a whole lot of sense...

Heh. My main worry with that commit was that we'd see the reverse
effect: somebody implicitly depending on the continued sharing of
pages in some odd splice situation, and where breaking the COW would
result in a performance degradation.

The fact that it went the other way instead is somewhat ironic.

But good.

I guess I'll just ping the stable people to say "yeah, put that in
stable too". It's a fix, and apparently it _helps_ performance for the
degenerate cases rather than hurting anything.

Linus

\
 
 \ /
  Last update: 2020-06-15 21:11    [W:0.110 / U:0.212 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site