perf kvm top: Limit guest kernel info message to once

'perf kvm top' shows a continual flurry of:
    Can't find guest [5201]'s kernel information

if it can't find the guest info and with a lot of VMs running a user has no
chance of reading them all. Limit message to once per guest.

Signed-off-by: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1343709095-7089-5-git-send-email-dsahern@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 11 insertions, 2 deletions

diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
index 34096275a7b5..68cd61ef6ac5 100644
--- a/tools/perf/builtin-top.c
+++ b/tools/perf/builtin-top.c
@@ -38,6 +38,7 @@
 #include "util/cpumap.h"
 #include "util/xyarray.h"
 #include "util/sort.h"
+#include "util/intlist.h"
 
 #include "util/debug.h"
 
@@ -706,8 +707,16 @@ static void perf_event__process_sample(struct perf_tool *tool,
         int err;
 
         if (!machine && perf_guest) {
-                pr_err("Can't find guest [%d]'s kernel information\n",
-                        event->ip.pid);
+                static struct intlist *seen;
+
+                if (!seen)
+                        seen = intlist__new();
+
+                if (!intlist__has_entry(seen, event->ip.pid)) {
+                        pr_err("Can't find guest [%d]'s kernel information\n",
+                                event->ip.pid);
+                        intlist__add(seen, event->ip.pid);
+                }
                 return;
         }