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author | Sean Christopherson <seanjc@google.com> | 2023-11-10 05:28:53 +0300 |
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committer | Sean Christopherson <seanjc@google.com> | 2024-02-01 20:35:48 +0300 |
commit | d2b321ea9380564510d281d45ccd2b424da14e7f (patch) | |
tree | 8f2e98b5310b214113728440196d7dc3ed12dc80 /arch/x86/kvm/pmu.h | |
parent | e5a65d4f723ab9997deab798c539e6bfd71f8440 (diff) | |
download | linux-d2b321ea9380564510d281d45ccd2b424da14e7f.tar.xz |
KVM: x86/pmu: Process only enabled PMCs when emulating events in software
Mask off disabled counters based on PERF_GLOBAL_CTRL *before* iterating
over PMCs to emulate (branch) instruction required events in software. In
the common case where the guest isn't utilizing the PMU, pre-checking for
enabled counters turns a relatively expensive search into a few AND uops
and a Jcc.
Sadly, PMUs without PERF_GLOBAL_CTRL, e.g. most existing AMD CPUs, are out
of luck as there is no way to check that a PMC isn't being used without
checking the PMC's event selector.
Cc: Konstantin Khorenko <khorenko@virtuozzo.com>
Link: https://lore.kernel.org/r/20231110022857.1273836-7-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Diffstat (limited to 'arch/x86/kvm/pmu.h')
0 files changed, 0 insertions, 0 deletions