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

From: Linus Torvalds
Date: Sun Feb 28 2010 - 15:10:24 EST



I haven't bisected this, but something slowed down in bootup on my machine
recently.

See the timestamps:

[ 0.000000] Linux version 2.6.33-01832-g30ff056
...
[ 0.010066] Enabled Interrupt-remapping
[ 0.010120] Setting APIC routing to physical flat
[ 0.010180] DRHD: handling fault status reg 2
[ 0.010582] ..TIMER: vector=0x30 apic1=0 pin1=2 apic2=-1 pin2=-1
[ 0.049955] CPU0: Genuine Intel(R) CPU 000 @ 3.20GHz stepping 04
[ 0.157195] Booting Node 0, Processors #1
[ 0.245179] CPU 1 MCA banks CMCI:2 CMCI:3 CMCI:5 SHD:6 SHD:8
[ 0.265332] #2
[ 0.353185] CPU 2 MCA banks CMCI:2 CMCI:3 CMCI:5 SHD:6 SHD:8
[ 0.373328] #3
[ 2.193277] CPU 3 MCA banks CMCI:2 CMCI:3 CMCI:5 SHD:6 SHD:8
[ 2.213379] #4
[ 2.301283] CPU 4 MCA banks SHD:2 SHD:3 SHD:5 SHD:6 SHD:8
[ 2.321391] #5
[ 2.417287] CPU 5 MCA banks SHD:2 SHD:3 SHD:5 SHD:6 SHD:8
[ 2.437356] #6
[ 2.525293] CPU 6 MCA banks SHD:2 SHD:3 SHD:5 SHD:6 SHD:8
[ 2.545354] #7
[ 2.633298] CPU 7 MCA banks SHD:2 SHD:3 SHD:5 SHD:6 SHD:8
[ 2.653423] Brought up 8 CPUs
[ 2.653571] Total of 8 processors activated (51201.44 BogoMIPS).

what happened there for almost 2 seconds in between CPU#3 and CPU#4?

It wasn't very fast before either, but it was way better:

[ 0.050298] CPU0: Genuine Intel(R) CPU 000 @ 3.20GHz stepping 04
[ 0.156725] Booting Node 0, Processors #1
[ 0.244410] CPU 1 MCA banks CMCI:2 CMCI:3 CMCI:5 SHD:6 SHD:8
[ 0.264458] #2
[ 0.352078] CPU 2 MCA banks CMCI:2 CMCI:3 CMCI:5 SHD:6 SHD:8
[ 0.372147] #3
[ 0.459746] CPU 3 MCA banks CMCI:2 CMCI:3 CMCI:5 SHD:6 SHD:8
[ 0.479838] #4
[ 0.567415] CPU 4 MCA banks SHD:2 SHD:3 SHD:5 SHD:6 SHD:8
[ 0.587446] #5
[ 0.683057] CPU 5 MCA banks SHD:2 SHD:3 SHD:5 SHD:6 SHD:8
[ 0.703081] #6
[ 0.790724] CPU 6 MCA banks SHD:2 SHD:3 SHD:5 SHD:6 SHD:8
[ 0.810748] #7
[ 0.898393] CPU 7 MCA banks SHD:2 SHD:3 SHD:5 SHD:6 SHD:8
[ 0.918412] Brought up 8 CPUs
[ 0.918562] Total of 8 processors activated (51203.34 BogoMIPS).

what is it that takes so long to bring those CPU's up?

Linus
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