diff options
| author | Janakarajan Natarajan <Janakarajan.Natarajan@amd.com> | 2019-11-05 20:16:55 +0300 |
|---|---|---|
| committer | Shuah Khan <skhan@linuxfoundation.org> | 2019-11-06 03:22:56 +0300 |
| commit | 6af2ed53f0402c09b36d2b38698e18a25ca732a7 (patch) | |
| tree | ea83341eecb9c5b048929e9aa75abf140ae48a3c /tools/power/cpupower/utils/helpers/cpuid.c | |
| parent | 7adafe541fe5e015261a92d39db8b163db477337 (diff) | |
| download | linux-6af2ed53f0402c09b36d2b38698e18a25ca732a7.tar.xz | |
cpupower: mperf_monitor: Update cpupower to use the RDPRU instruction
AMD Zen 2 introduces the RDPRU instruction which can be used to access some
processor registers which are typically only accessible in privilege level
0. ECX specifies the register to read and EDX:EAX will contain the value read.
ECX: 0 - Register MPERF
1 - Register APERF
This has the added advantage of not having to use the msr module, since the
userspace to kernel transitions which occur during each read_msr() might
cause APERF and MPERF to go out of sync.
Signed-off-by: Janakarajan Natarajan <Janakarajan.Natarajan@amd.com>
Acked-by: Thomas Renninger <trenn@suse.de>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
Diffstat (limited to 'tools/power/cpupower/utils/helpers/cpuid.c')
| -rw-r--r-- | tools/power/cpupower/utils/helpers/cpuid.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/tools/power/cpupower/utils/helpers/cpuid.c b/tools/power/cpupower/utils/helpers/cpuid.c index 5cc39d4e23ed..73bfafc60e9b 100644 --- a/tools/power/cpupower/utils/helpers/cpuid.c +++ b/tools/power/cpupower/utils/helpers/cpuid.c @@ -131,6 +131,10 @@ out: if (ext_cpuid_level >= 0x80000007 && (cpuid_edx(0x80000007) & (1 << 9))) cpu_info->caps |= CPUPOWER_CAP_AMD_CBP; + + if (ext_cpuid_level >= 0x80000008 && + cpuid_ebx(0x80000008) & (1 << 4)) + cpu_info->caps |= CPUPOWER_CAP_AMD_RDPRU; } if (cpu_info->vendor == X86_VENDOR_INTEL) { |