Re: [RFC PATCH] perf: honouring the cpuid for number of fixed counters in hypervisors
From: Peter Zijlstra
Date: Sun Oct 16 2016 - 09:51:56 EST
On Thu, Oct 13, 2016 at 01:28:09AM -0700, Imre Palik wrote:
> + if (version > 1) {
> + unsigned int ecx = cpuid_ecx(1);
> +
> + if (ecx >> 31)
What is this magic, undocumented gunk doing? Is that supposed to be
static_cpu_has(X86_FEATURE_HYPERVISOR) ?