From: Robert R. <rob...@am...> - 2009-05-06 16:40:30
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On 06.05.09 16:47:20, Andi Kleen wrote: > On Wed, May 06, 2009 at 02:39:12PM +0200, Robert Richter wrote: > > The current userland does not yet fully support all cpu types > > implemented in the kernel. With the module parameter oprofile.cpu_type > > a certain cpu type can be reported to the oprofile userland and thus > > makes the kernel usable with current distros. > > On Intel systems forcing archperfmon is the only one that makes sense > nd only if the CPU supports arch perfmon(btw that's already in my patchkit > which you haven't commented on so far) > > I don't thinking forcing core2 on a system like Nehalem with completely > different events is a good idea though. This just means if the user > selects anything unusual they will get junk data, which is just > a bad design. It is a kernel parameter, and users should know what they are doing and what the risks are. I assume counting cpu clk unhalted will work and some other events too. So the patch does not hurt. > Also if you force core2 on a P4 system the kernel will just oops > because it will access MSRs that are not there. So I don't think > that's a good idea. It anables core_2 only on family 6 (ppro implementation). > > It means you have to update oprofile userland at least once until > you have arch perfmon support, but I think even Linus will be able > to do that :) Hopefully Maynard will do a new release soon. I agree, a new release of the userland would be the best. But till then it is at least 1-2 months to go. > The force of core2 is nacked from my side. I do not have any passion with this patch, What I have in mind is "oprofile sucks", and this patch would make oprofile more usable. -Robert -- Advanced Micro Devices, Inc. Operating System Research Center email: rob...@am... |