Re: [GIT PULL] x86/cpu changes for v2.6.34

From: Linus Torvalds
Date: Sun Feb 28 2010 - 15:46:15 EST




On Sun, 28 Feb 2010, Linus Torvalds wrote:
>
> I haven't bisected this, but something slowed down in bootup on my machine
> recently.

Hmm. I take that back. It's not consistent, and it's not recent after all.

It comes and goes:

[torvalds@nehalem linux]$ grep "CPU 7 MCA" /var/log/messages-* /var/log/messages | cut -d: -f5-
[ 0.898396] CPU 7 MCA banks SHD:2 SHD:3 SHD:5 SHD:6 SHD:8
[ 0.898400] CPU 7 MCA banks SHD:2 SHD:3 SHD:5 SHD:6 SHD:8
[ 1.596240] CPU 7 MCA banks SHD:2 SHD:3 SHD:5 SHD:6 SHD:8
[ 0.898394] CPU 7 MCA banks SHD:2 SHD:3 SHD:5 SHD:6 SHD:8
[ 1.600229] CPU 7 MCA banks SHD:2 SHD:3 SHD:5 SHD:6 SHD:8
[ 0.898395] CPU 7 MCA banks SHD:2 SHD:3 SHD:5 SHD:6 SHD:8
[ 0.901211] CPU 7 MCA banks SHD:2 SHD:3 SHD:5 SHD:6 SHD:8
[ 2.633298] CPU 7 MCA banks SHD:2 SHD:3 SHD:5 SHD:6 SHD:8
[ 0.898393] CPU 7 MCA banks SHD:2 SHD:3 SHD:5 SHD:6 SHD:8
[ 0.901210] CPU 7 MCA banks SHD:2 SHD:3 SHD:5 SHD:6 SHD:8
[ 0.898395] CPU 7 MCA banks SHD:2 SHD:3 SHD:5 SHD:6 SHD:8
[ 0.898393] CPU 7 MCA banks SHD:2 SHD:3 SHD:5 SHD:6 SHD:8
[ 0.898393] CPU 7 MCA banks SHD:2 SHD:3 SHD:5 SHD:6 SHD:8
[ 0.898402] CPU 7 MCA banks SHD:2 SHD:3 SHD:5 SHD:6 SHD:8
[ 0.901213] CPU 7 MCA banks SHD:2 SHD:3 SHD:5 SHD:6 SHD:8
[ 0.898392] CPU 7 MCA banks SHD:2 SHD:3 SHD:5 SHD:6 SHD:8
[ 0.898395] CPU 7 MCA banks SHD:2 SHD:3 SHD:5 SHD:6 SHD:8
[ 1.601467] CPU 7 MCA banks SHD:2 SHD:3 SHD:5 SHD:6 SHD:8
[ 0.898401] CPU 7 MCA banks SHD:2 SHD:3 SHD:5 SHD:6 SHD:8
[ 0.898395] CPU 7 MCA banks SHD:2 SHD:3 SHD:5 SHD:6 SHD:8
[ 0.898397] CPU 7 MCA banks SHD:2 SHD:3 SHD:5 SHD:6 SHD:8

note how it's pretty consistently at about the 0.89s mark, but then
there's a _couple_ of times when it's taken rather longer to boot. But the
delay is always in that CPU bringup phase, because doing the same grep for
"CPU 0 MCA" gives consistently low numbers (0.0005s).

Linus
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