Re: [PATCH 30/35] perf intel-pt: Track guest context switches

Ian Rogers
2022-07-20T01:17:45Z

On Mon, Jul 11, 2022 at 2:33 AM Adrian Hunter <adrian.hunter@intel.com> wrote:
>
> Use guest context switch events to keep track of which guest thread is
> running on a particular guest machine and VCPU.
>
> Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>

Acked-by: Ian Rogers <irogers@google.com>

Thanks,
Ian

> ---
> tools/perf/util/intel-pt.c | 23 +++++++++++++++++++++++
> 1 file changed, 23 insertions(+)
>
> diff --git a/tools/perf/util/intel-pt.c b/tools/perf/util/intel-pt.c
> index a8798b5bb311..98b097fec476 100644
> --- a/tools/perf/util/intel-pt.c
> +++ b/tools/perf/util/intel-pt.c
> @@ -78,6 +78,7 @@ struct intel_pt {
> bool use_thread_stack;
> bool callstack;
> bool cap_event_trace;
> + bool have_guest_sideband;
> unsigned int br_stack_sz;
> unsigned int br_stack_sz_plus;
> int have_sched_switch;
> @@ -3079,6 +3080,25 @@ static int intel_pt_context_switch_in(struct intel_pt *pt,
> return machine__set_current_tid(pt->machine, cpu, pid, tid);
> }
>
> +static int intel_pt_guest_context_switch(struct intel_pt *pt,
> + union perf_event *event,
> + struct perf_sample *sample)
> +{
> + bool out = event->header.misc & PERF_RECORD_MISC_SWITCH_OUT;
> + struct machines *machines = &pt->session->machines;
> + struct machine *machine = machines__find(machines, sample->machine_pid);
> +
> + pt->have_guest_sideband = true;
> +
> + if (out)
> + return 0;
> +
> + if (!machine)
> + return -EINVAL;
> +
> + return machine__set_current_tid(machine, sample->vcpu, sample->pid, sample->tid);
> +}
> +
> static int intel_pt_context_switch(struct intel_pt *pt, union perf_event *event,
> struct perf_sample *sample)
> {
> @@ -3086,6 +3106,9 @@ static int intel_pt_context_switch(struct intel_pt *pt, union perf_event *event,
> pid_t pid, tid;
> int cpu, ret;
>
> + if (perf_event__is_guest(event))
> + return intel_pt_guest_context_switch(pt, event, sample);
> +
> cpu = sample->cpu;
>
> if (pt->have_sched_switch == 3) {
> --
> 2.25.1
>