Messages in this thread | | | Date | Mon, 22 May 2017 21:24:45 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH 2/2] perf/x86/intel, watchdog: Switch NMI watchdog to ref cycles on x86 |
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On Mon, May 22, 2017 at 04:58:04PM +0000, Liang, Kan wrote: > > > > On Fri, May 19, 2017 at 10:06:22AM -0700, kan.liang@intel.com wrote: > > > This patch was once merged, but reverted later. > > > Because ref-cycles can not be used anymore when watchdog is enabled. > > > The commit is 44530d588e142a96cf0cd345a7cb8911c4f88720 > > > > > > The patch 1/2 has extended the ref-cycles to GP counter. The concern > > > should be gone. > > > > So its not a problem if every Atom prior to Goldmont, and all Core/Core2 > > products regress? > > > > P6 and P4 you've entirely broken, as they don't have REF_CPU_CYCLES at all. > > > > So no, I don't think this is right even now. > > > > Right, the patch 1/2 doesn't cover all platforms. > I will only apply the patch for the platforms, > which have ref cycles on GP counters.
Right, so if you move the weak function into arch/x86/events/core.c and simply test for x86_pmu.this_ref_alis_function_thing being !NULL that should all work.
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