2.6.35: cpu_idle bug report / on i7 870 cpu (x86_64)

From: Justin Piszcz
Date: Fri Aug 06 2010 - 18:10:01 EST


Hi,

When cpu_idle is used alongside a core i7 cpu w/cpufreq, the system exhibits delays when typing into a terminal via ssh or VNC, I had changed a few options from 2.6.34 -> 2.6.35 and did not think the cpu_idle would be at fault; however, after going through all of the options and disabling it, the problem went away.

< > Cpuidle Driver for Intel Processors

The system lags every so often when cpu_idle is enabled. It is quite annoying.

All disk subsystems/CPU/etc are OK-- that option causes some nasty side effects.

Kernel config: (w/cpu_idle) - exhibits the problem.
http://home.comcast.net/~jpiszcz/20100806/config-20100806.1281129405

Removed cpu_idle, problem is gone.
http://home.comcast.net/~jpiszcz/20100806/config-20100806.1281131518

In addition, sometimes the system did not reboot (instead I hear the speaker whining solid, not beeping, just a constant whine).

And sometimes it failed to reboot between kernel rebuilds.

After cpu_idle has been removed from the kernel, all problems have went away.

This may have already been reported but I did not find anything on it.

Is this driver safe for i7 CPUs and/or who should be using it?

Justin.
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