Will Deacon <will.deacon@xxxxxxx> writes: > On Wed, Jan 18, 2017 at 01:01:40PM +0000, Punit Agrawal wrote: >> Mark Rutland <mark.rutland@xxxxxxx> writes: >> >> > On Wed, Jan 18, 2017 at 11:21:21AM +0000, Marc Zyngier wrote: >> >> On 10/01/17 11:38, Punit Agrawal wrote: >> >> > +#define VM_MASK GENMASK_ULL(31, 0) >> >> > +#define EVENT_MASK GENMASK_ULL(32, 39) >> >> > +#define EVENT_SHIFT (32) >> >> > + >> >> > +#define to_pid(cfg) ((cfg) & VM_MASK) >> >> > +#define to_event(cfg) (((cfg) & EVENT_MASK) >> EVENT_SHIFT) >> >> > + >> >> > +PMU_FORMAT_ATTR(vm, "config:0-31"); >> >> > +PMU_FORMAT_ATTR(event, "config:32-39"); >> >> >> >> I'm a bit confused by these. Can't you get the PID of the VM you're >> >> tracing directly from perf, without having to encode things? >> >> With perf attached to a PID, the event gets scheduled out when the task >> is context switched. As the PID of the controlling process was used, >> none of the vCPU events were counted. > > So it sounds like userspace needs to deal with this by attaching to the PIDs > of the vCPUs. Given that perf kvm seems to have knowledge of vCPUs, it would > be nice to know why that logic isn't reusable here. Take a look in > tools/perf/builtin-kvm.c and if it's not up to the job, then perhaps it can > be improved. Thanks for the pointer. I'll have a play with perf kvm to see if it can be leveraged here. > > Will > _______________________________________________ > kvmarm mailing list > kvmarm@xxxxxxxxxxxxxxxxxxxxx > https://lists.cs.columbia.edu/mailman/listinfo/kvmarm -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
