Bad performance after suspend on Intel i7 and i5

Bad performance after suspend on Intel i7 and i5

[Florian Pritz]

Hi,

When I run make -j12 (on a kernel tree) all 8 cores are at 100% each.
(Can also be tested with stress -c 8 or any multithreaded program)
After a suspend2ram (using pm-suspend) only one single core is at 100%
and the others are somewhere between 0% and 10% though not 100% like
before.

This bug is reproduceable on at least 3 machines, running on i7-920,
i7-860 and i5-520M.
Tested kernels are 2.6.33-ARCH (config [1]) , 2.6.32.9-ARCH and
2.6.34-rc1-00005-g522dba7 (only be me; config [2]).

/proc/cpuinfo shows 8 cpus before and after suspend.

My own hardware:
CPU: Intel i7-920
Board: Gigabyte GA-EX58-UD4P [3]
RAM: 8GB
Arch: x86_64 (all 3)
Distribution: Archlinux (all 3)

I don't know of any older good kernel, so sadly can't bisect anything.

Thanks for looking into that issue.

[1]
http://repos.archlinux.org/wsvn/packages/kernel26/trunk/config.x86_64?rev=70484&peg=70484
[2] http://flo.xssn.at/~flo/tmp/kernel-config
[3]
http://www.gigabyte.com.tw/Products/Motherboard/Products_Overview.aspx?ProductID=2986

-- 
Greetings,
Florian Pritz -- {flo,bluewind}@server-speed.net