Messages in this thread | | | Date | Wed, 8 Dec 2010 09:39:22 -0500 | From | Vivek Goyal <> | Subject | Re: perf hw in kexeced kernel broken in tip |
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On Wed, Dec 08, 2010 at 09:01:03AM -0500, Don Zickus wrote: > On Wed, Dec 08, 2010 at 12:30:20AM +0100, Peter Zijlstra wrote: > > On Thu, 2010-12-02 at 11:15 -0500, Don Zickus wrote: > > > > > Vivek suggested to me this morning that I should just blantantly disable the > > > perf counter during init when running my test. > > > > Nah, we should actively scan for that during the bring-up and kill > > hw-perf when we find an enable bit set, some BIOSes actively use the > > PMU, this is something that should be discouraged. > > Ok, the reboot notifier addresses the kexec problem but doesn't fix it > though (I have to test to confirm that, comments below). The bios check > should catch those situations (ironically I stumbled upon a machine with > this problem, so I will test your patch with it, though it only uses perf > counter 0). The kdump problem will still exist, not sure if we care and > perhaps we should document in the changelog that we know kdump is still > broken (unless we do care).
Can't think why would somebody like to use performance counters in kdump kernel. So that probably should not be a concern.
Vivek
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