perf tools: Fix counter sample frequency breakage

Commit 42e59d7d19dc4b4 switched to a default sample frequency of
1KHz, which overrides any user supplied count, causing sched, top
and timechart to miss events due to their discrete events
being flagged PERF_SAMPLE_PERIOD.

Override default sample frequency when the user profides a
period count, and make both record and top honor that user
supplied option.

Signed-off-by: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arjan van de Ven <arjan@infradead.org>
LKML-Reference: <1255326963.15107.2.camel@marge.simson.net>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 13 insertions, 1 deletions

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 59af03d80d07..4e3a374e7aa7 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -26,7 +26,7 @@
 
 static int                      fd[MAX_NR_CPUS][MAX_COUNTERS];
 
-static long                     default_interval                = 100000;
+static long                     default_interval                =      0;
 
 static int                      nr_cpus                         =      0;
 static unsigned int             page_size;
@@ -730,6 +730,18 @@ int cmd_record(int argc, const char **argv, const char *prefix __used)
                 attrs[0].config = PERF_COUNT_HW_CPU_CYCLES;
         }
 
+        /*
+         * User specified count overrides default frequency.
+         */
+        if (default_interval)
+                freq = 0;
+        else if (freq) {
+                default_interval = freq;
+        } else {
+                fprintf(stderr, "frequency and count are zero, aborting\n");
+                exit(EXIT_FAILURE);
+        }
+
         for (counter = 0; counter < nr_counters; counter++) {
                 if (attrs[counter].sample_period)
                         continue;