perf_counter tools: Split display into reading and printing

We introduce the extra pass to allow the print-out to possibly
rely on already read counters.

[ Impact: cleanup ]

Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: John Kacur <jkacur@redhat.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 34 insertions, 6 deletions

diff --git a/Documentation/perf_counter/builtin-stat.c b/Documentation/perf_counter/builtin-stat.c
index 6a2936150f28..0c92eb725526 100644
--- a/Documentation/perf_counter/builtin-stat.c
+++ b/Documentation/perf_counter/builtin-stat.c
@@ -71,6 +71,9 @@ static const unsigned int default_count[] = {
           10000,
 };
 
+static __u64                    event_res[MAX_COUNTERS][3];
+static __u64                    event_scaled[MAX_COUNTERS];
+
 static void create_perfstat_counter(int counter)
 {
         struct perf_counter_hw_event hw_event;
@@ -123,16 +126,19 @@ static inline int nsec_counter(int counter)
 }
 
 /*
- * Print out the results of a single counter:
+ * Read out the results of a single counter:
  */
-static void print_counter(int counter)
+static void read_counter(int counter)
 {
-        __u64 count[3], single_count[3];
+        __u64 *count, single_count[3];
         ssize_t res;
         int cpu, nv;
         int scaled;
 
+        count = event_res[counter];
+
         count[0] = count[1] = count[2] = 0;
+
         nv = scale ? 3 : 1;
         for (cpu = 0; cpu < nr_cpus; cpu ++) {
                 res = read(fd[cpu][counter], single_count, nv * sizeof(__u64));
@@ -148,16 +154,35 @@ static void print_counter(int counter)
         scaled = 0;
         if (scale) {
                 if (count[2] == 0) {
-                        fprintf(stderr, " %14s  %-20s\n",
-                                "<not counted>", event_name(counter));
+                        event_scaled[counter] = -1;
+                        count[0] = 0;
                         return;
                 }
+
                 if (count[2] < count[1]) {
-                        scaled = 1;
+                        event_scaled[counter] = 1;
                         count[0] = (unsigned long long)
                                 ((double)count[0] * count[1] / count[2] + 0.5);
                 }
         }
+}
+
+/*
+ * Print out the results of a single counter:
+ */
+static void print_counter(int counter)
+{
+        __u64 *count;
+        int scaled;
+
+        count = event_res[counter];
+        scaled = event_scaled[counter];
+
+        if (scaled == -1) {
+                fprintf(stderr, " %14s  %-20s\n",
+                        "<not counted>", event_name(counter));
+                return;
+        }
 
         if (nsec_counter(counter)) {
                 double msecs = (double)count[0] / 1000000;
@@ -214,6 +239,9 @@ static int do_perfstat(int argc, const char **argv)
         fprintf(stderr, "\n");
 
         for (counter = 0; counter < nr_counters; counter++)
+                read_counter(counter);
+
+        for (counter = 0; counter < nr_counters; counter++)
                 print_counter(counter);