[PATCH 02/11] perf kvm: set name for VM process in guest machine

From: David Ahern
Date: Fri Jul 20 2012 - 19:28:30 EST


COMM events are not generated in the context of a guest machine, so the
thread name is never set for the VMM process. For example, the qemu-kvm
name applies to the process in the host machine, not the guest machine.
So, samples for guest machines are currently displayed as:

99.67% :5671 [unknown] [g] 0xffffffff81366b41

where 5671 is the pid of the VMM. With this patch the samples in the guest
machine are shown as:

18.43% [guest/5671] [unknown] [g] 0xffffffff810d68b7

Signed-off-by: David Ahern <dsahern@xxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
---
tools/perf/util/map.c | 17 ++++++++++++++++-
1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/map.c b/tools/perf/util/map.c
index a1f4e36..8668569 100644
--- a/tools/perf/util/map.c
+++ b/tools/perf/util/map.c
@@ -7,6 +7,7 @@
#include <stdio.h>
#include <unistd.h>
#include "map.h"
+#include "thread.h"

const char *map_type__name[MAP__NR_TYPES] = {
[MAP__FUNCTION] = "Functions",
@@ -585,7 +586,21 @@ int machine__init(struct machine *self, const char *root_dir, pid_t pid)
self->kmaps.machine = self;
self->pid = pid;
self->root_dir = strdup(root_dir);
- return self->root_dir == NULL ? -ENOMEM : 0;
+ if (self->root_dir == NULL)
+ return -ENOMEM;
+
+ if (pid != HOST_KERNEL_ID) {
+ struct thread *thread = machine__findnew_thread(self, pid);
+ char comm[64];
+
+ if (thread == NULL)
+ return -ENOMEM;
+
+ snprintf(comm, sizeof(comm), "[guest/%d]", pid);
+ thread__set_comm(thread, comm);
+ }
+
+ return 0;
}

static void dsos__delete(struct list_head *self)
--
1.7.10.1

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