| Message ID | 20220711093218.10967-13-adrian.hunter@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | perf intel-pt: Add support for tracing virtual machine user space on the host | expand |
On Mon, Jul 11, 2022 at 2:33 AM Adrian Hunter <adrian.hunter@intel.com> wrote: > > It is possible to know which guest machine was running at a point in time > based on the PID of the currently running host thread. That is, perf > identifies guest machines by the PID of the hypervisor. > > To determine the guest CPU, put it on the hypervisor (QEMU) thread for > that VCPU. > > This is done when processing the id_index which provides the necessary > information. > > Signed-off-by: Adrian Hunter <adrian.hunter@intel.com> > --- > tools/perf/util/session.c | 18 ++++++++++++++++++ > tools/perf/util/thread.c | 1 + > tools/perf/util/thread.h | 1 + > 3 files changed, 20 insertions(+) > > diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c > index 1af981d5ad3c..91a091c35945 100644 > --- a/tools/perf/util/session.c > +++ b/tools/perf/util/session.c > @@ -2769,6 +2769,20 @@ static int perf_session__register_guest(struct perf_session *session, pid_t mach > return 0; > } > > +static int perf_session__set_guest_cpu(struct perf_session *session, pid_t pid, > + pid_t tid, int guest_cpu) > +{ > + struct machine *machine = &session->machines.host; > + struct thread *thread = machine__findnew_thread(machine, pid, tid); > + > + if (!thread) > + return -ENOMEM; > + thread->guest_cpu = guest_cpu; > + thread__put(thread); > + > + return 0; > +} > + > int perf_event__process_id_index(struct perf_session *session, > union perf_event *event) > { > @@ -2845,6 +2859,10 @@ int perf_event__process_id_index(struct perf_session *session, > last_pid = sid->machine_pid; > perf_guest = true; > } > + > + ret = perf_session__set_guest_cpu(session, sid->machine_pid, e->tid, e2->vcpu); > + if (ret) > + return ret; > } > return 0; > } > diff --git a/tools/perf/util/thread.c b/tools/perf/util/thread.c > index 665e5c0618ed..e3e5427e1c3c 100644 > --- a/tools/perf/util/thread.c > +++ b/tools/perf/util/thread.c > @@ -47,6 +47,7 @@ struct thread *thread__new(pid_t pid, pid_t tid) > thread->tid = tid; > thread->ppid = -1; > thread->cpu = -1; > + thread->guest_cpu = -1; > thread->lbr_stitch_enable = false; > INIT_LIST_HEAD(&thread->namespaces_list); > INIT_LIST_HEAD(&thread->comm_list); > diff --git a/tools/perf/util/thread.h b/tools/perf/util/thread.h > index b066fb30d203..241f300d7d6e 100644 > --- a/tools/perf/util/thread.h > +++ b/tools/perf/util/thread.h > @@ -39,6 +39,7 @@ struct thread { > pid_t tid; > pid_t ppid; > int cpu; > + int guest_cpu; /* For QEMU thread */ Could we tweak the comments here to be something like: int cpu; /* The CPU the thread is currently running on or the CPU of the hypervisor thread. */ int guest_cpu; /* The CPU within a guest (QEMU) that's running. */ Does -1 convey meaning beyond uninitialized, like with the 'any' CPU perf_event_open argument? Thanks, Ian > refcount_t refcnt; > bool comm_set; > int comm_len; > -- > 2.25.1 >
diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c index 1af981d5ad3c..91a091c35945 100644 --- a/tools/perf/util/session.c +++ b/tools/perf/util/session.c @@ -2769,6 +2769,20 @@ static int perf_session__register_guest(struct perf_session *session, pid_t mach return 0; } +static int perf_session__set_guest_cpu(struct perf_session *session, pid_t pid, + pid_t tid, int guest_cpu) +{ + struct machine *machine = &session->machines.host; + struct thread *thread = machine__findnew_thread(machine, pid, tid); + + if (!thread) + return -ENOMEM; + thread->guest_cpu = guest_cpu; + thread__put(thread); + + return 0; +} + int perf_event__process_id_index(struct perf_session *session, union perf_event *event) { @@ -2845,6 +2859,10 @@ int perf_event__process_id_index(struct perf_session *session, last_pid = sid->machine_pid; perf_guest = true; } + + ret = perf_session__set_guest_cpu(session, sid->machine_pid, e->tid, e2->vcpu); + if (ret) + return ret; } return 0; } diff --git a/tools/perf/util/thread.c b/tools/perf/util/thread.c index 665e5c0618ed..e3e5427e1c3c 100644 --- a/tools/perf/util/thread.c +++ b/tools/perf/util/thread.c @@ -47,6 +47,7 @@ struct thread *thread__new(pid_t pid, pid_t tid) thread->tid = tid; thread->ppid = -1; thread->cpu = -1; + thread->guest_cpu = -1; thread->lbr_stitch_enable = false; INIT_LIST_HEAD(&thread->namespaces_list); INIT_LIST_HEAD(&thread->comm_list); diff --git a/tools/perf/util/thread.h b/tools/perf/util/thread.h index b066fb30d203..241f300d7d6e 100644 --- a/tools/perf/util/thread.h +++ b/tools/perf/util/thread.h @@ -39,6 +39,7 @@ struct thread { pid_t tid; pid_t ppid; int cpu; + int guest_cpu; /* For QEMU thread */ refcount_t refcnt; bool comm_set; int comm_len;
It is possible to know which guest machine was running at a point in time based on the PID of the currently running host thread. That is, perf identifies guest machines by the PID of the hypervisor. To determine the guest CPU, put it on the hypervisor (QEMU) thread for that VCPU. This is done when processing the id_index which provides the necessary information. Signed-off-by: Adrian Hunter <adrian.hunter@intel.com> --- tools/perf/util/session.c | 18 ++++++++++++++++++ tools/perf/util/thread.c | 1 + tools/perf/util/thread.h | 1 + 3 files changed, 20 insertions(+)