diff options
| author | Like Xu <like.xu@linux.intel.com> | 2020-06-13 16:09:49 +0800 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2020-07-02 15:51:46 +0200 |
| commit | 097e4311cda952dfb047f2a49d35aa5de500d474 (patch) | |
| tree | 9dc6dff0a1c21956573c584478be689113e72e0c /arch/x86/events/core.c | |
| parent | b2d6504761a50b9493eb4b20f6e188b673f20c32 (diff) | |
perf/x86: Add constraint to create guest LBR event without hw counter
The hypervisor may request the perf subsystem to schedule a time window
to directly access the LBR records msrs for its own use. Normally, it would
create a guest LBR event with callstack mode enabled, which is scheduled
along with other ordinary LBR events on the host but in an exclusive way.
To avoid wasting a counter for the guest LBR event, the perf tracks its
hw->idx via INTEL_PMC_IDX_FIXED_VLBR and assigns it with a fake VLBR
counter with the help of new vlbr_constraint. As with the BTS event,
there is actually no hardware counter assigned for the guest LBR event.
Signed-off-by: Like Xu <like.xu@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200514083054.62538-5-like.xu@linux.intel.com
Diffstat (limited to 'arch/x86/events/core.c')
| -rw-r--r-- | arch/x86/events/core.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c index 15cb7af7db18..d740c861724c 100644 --- a/arch/x86/events/core.c +++ b/arch/x86/events/core.c @@ -1104,6 +1104,7 @@ static inline void x86_assign_hw_event(struct perf_event *event, switch (hwc->idx) { case INTEL_PMC_IDX_FIXED_BTS: + case INTEL_PMC_IDX_FIXED_VLBR: hwc->config_base = 0; hwc->event_base = 0; break; |