Messages in this thread | | | Subject | Re: [PATCH] perf_event use rdpmc rather than rdmsr when possible in kernel | From | Peter Zijlstra <> | Date | Mon, 27 Feb 2012 17:18:38 +0100 |
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On Mon, 2012-02-27 at 11:06 -0500, Vince Weaver wrote: > > > + new_raw_count=native_read_pmc(hwc->event_base_rdpmc); > > > > That really wants to be rdpmc(), bypassing paravirt like that isn't > > nice. > > I couldn't find another usable rdpmc() call in the kernel. Should I add > one? I admit I hadn't thought that this might break VMs not expecting > rdpmc calls from the kernel.
arch/x86/include/asm/msr.h
#define rdpmc(counter, low, high) \ do { \ u64 _l = native_read_pmc((counter)); \ (low) = (u32)_l; \ (high) = (u32)(_l >> 32); \ } while (0)
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