Andi Kleen <[email protected]> writes: > +/* > + * Disable the PT trace for debugging purposes. > + */ > +void pt_disable(void) > +{ > + u64 val; > + > + if (!boot_cpu_has(X86_FEATURE_INTEL_PT)) > + return; > + > + rdmsrl_safe(MSR_IA32_RTIT_CTL, &val); > + val &= ~RTIT_CTL_TRACEEN; > + wrmsrl_safe(MSR_IA32_RTIT_CTL, val); > +} > +EXPORT_SYMBOL(pt_disable);
This will create unexplainable gaps in the trace, at least we should output RECORD_AUX when this happens, maybe add a flag for "had to stop the trace for reasons external to perf". Also, I can't tell if this is called from an atomic context. But I'd suggest something more generic like perf_pmu_off($pmu): - we already have the code to stop the output; - this won't be a driver-specific api then; - this will be reflected in the event hw state; - it will also go through the driver's callbacks, so its internal states will actually match the reality; - will work equally well for intel_bts or the ARM/Coresight tracers. Regards, -- Alex
