Re: REGRESSION: Performance regressions from switching anon_vma->lock to mutex

Peter Zijlstra
2011-06-15T10:59:37Z

On Wed, 2011-06-15 at 12:36 +0200, Peter Zijlstra wrote:
> On Tue, 2011-06-14 at 17:29 -0700, Tim Chen wrote:
> > MOSBENCH test suite.
>
> Argh, I'm trying to get this thing to run, but its all snake poo..
>
> /me takes up a heavy club and goes snake hunting, should make a pretty
> hat or something.

Sweet, I've got meself a snake-skin hat!

The first thing that stood out when running it was:

31694 root 20 0 26660 1460 1212 S 17.5 0.0 0:01.97 exim
7 root -2 19 0 0 0 S 12.7 0.0 0:06.14 rcuc0
24 root -2 19 0 0 0 S 11.7 0.0 0:04.15 rcuc3
34 root -2 19 0 0 0 S 11.7 0.0 0:04.10 rcuc5
39 root -2 19 0 0 0 S 11.7 0.0 0:06.38 rcuc6
44 root -2 19 0 0 0 S 11.7 0.0 0:04.53 rcuc7
49 root -2 19 0 0 0 S 11.7 0.0 0:04.11 rcuc8
79 root -2 19 0 0 0 S 11.7 0.0 0:03.91 rcuc14
89 root -2 19 0 0 0 S 11.7 0.0 0:03.90 rcuc16
110 root -2 19 0 0 0 S 11.7 0.0 0:03.90 rcuc20
120 root -2 19 0 0 0 S 11.7 0.0 0:03.82 rcuc22
13 root -2 19 0 0 0 S 10.7 0.0 0:04.37 rcuc1
19 root -2 19 0 0 0 S 10.7 0.0 0:04.19 rcuc2
29 root -2 19 0 0 0 S 10.7 0.0 0:04.12 rcuc4
54 root -2 19 0 0 0 S 10.7 0.0 0:04.11 rcuc9
59 root -2 19 0 0 0 S 10.7 0.0 0:04.40 rcuc10
64 root -2 19 0 0 0 R 10.7 0.0 0:04.17 rcuc11
69 root -2 19 0 0 0 R 10.7 0.0 0:04.23 rcuc12
84 root -2 19 0 0 0 S 10.7 0.0 0:03.90 rcuc15
95 root -2 19 0 0 0 S 10.7 0.0 0:03.99 rcuc17
100 root -2 19 0 0 0 S 10.7 0.0 0:03.88 rcuc18
105 root -2 19 0 0 0 S 10.7 0.0 0:04.14 rcuc19
125 root -2 19 0 0 0 S 10.7 0.0 0:03.79 rcuc23
74 root -2 19 0 0 0 S 9.7 0.0 0:04.33 rcuc13
115 root -2 19 0 0 0 R 9.7 0.0 0:03.82 rcuc21

Which is an impressive amount of RCU usage..