Bug 24742

Summary: Core i7 loses its multithreading capability after suspend
Product: Power Management Reporter: Keivan Moradi (k.moradi)
Component: Hibernation/SuspendAssignee: power-management_other
Status: CLOSED CODE_FIX    
Severity: normal CC: rjw
Priority: P1    
Hardware: All   
OS: Linux   
Kernel Version: 2.6.34 r12 gentoo-sources Tree: Mainline
Regression: No
Bug Depends on:    
Bug Blocks: 7216    

Description Keivan Moradi 2010-12-12 14:31:29 UTC
On my gentoo-linux system (2.6.34-gentoo-sources amd64), with a xeon 5540 (core i7) , each time I resume after the command "pm-suspend" (suspend to RAM), mutlithreading capabilities almost disappear. More specifically, two distinct programs can use 2 distinct cores at full rate, but a single program is limited to only one core (for one instance of a multithreaded program as well as multiple instances of a single threaded program, e.g. "make -j 4" for gcc). So I end up rebooting the system. Any help appreciated!

There are other people have this problem. this is a upstream bug.

http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=580901

http://codeme.gotdns.com/2010/04/30/core-i7-on-linux-loses-its-multithreading-capability-after-suspend/

http://superuser.com/questions/136291/core-i7-on-linux-loses-its-multithreading-capability-after-suspend

also these bug reports may be related to this one

https://bugzilla.kernel.org/show_bug.cgi?id=16567

https://bugzilla.kernel.org/show_bug.cgi?id=13885
Comment 1 Rafael J. Wysocki 2011-01-16 22:45:54 UTC
Does the problem still occur with 2.6.37?
Comment 2 Keivan Moradi 2011-01-17 00:25:16 UTC
problem solved in 2.6.36