Messages in this thread | | | Date | Fri, 26 Aug 2011 10:39:49 -0400 | From | Don Zickus <> | Subject | Re: [V3][PATCH 0/6] x86, nmi: new NMI handling routines |
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On Fri, Aug 26, 2011 at 11:44:57AM +0200, Peter Zijlstra wrote: > On Thu, 2011-08-25 at 12:45 -0400, Don Zickus wrote: > > I spent some time hacking and came up with this patch. I tested it on my > > core2quad machine trying to enable all the NMI handler I could, mainly > > perf and kgdb (and oprofile too when perf was disabled). Everything seems > > to work correctly. If people are ok with this approach, I'll try and test > > this on more machines. > > Right, code looks OK, the only worry that remains is overhead, always > running all handlers must cost..
Yeah nothing is free. My only counter argument is I removed the case statements in the handlers, so it speeds things up a tiny bit. Also most machines only seem to have perf and the arch_backtrace handler registered, with modern intel boxes probably registering the ghes handler too.
There really isn't much there, at least currently. I would break up the handler more if I knew a quicker way to distinguish between something like a self-IPI NMI vs. an on-chip NMI like perf. Then again those NMIs probably aren't latched differently unlike the external one sitting in the IOAPIC(??).
Cheers, Don
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