perf bench: Fix memcpy/memset output

The memcpy and memset benchmarks return bogus results when iterations >
0 because the iterations value is not taken into account when
calculating the final result:

 $ perf bench mem memset --only-prefault --length 1GB --iterations 1
 # Running 'mem/memset' benchmark:
 # Copying 1GB Bytes ...

       20.798669 GB/Sec (with prefault)
 $ perf bench mem memset --only-prefault --length 1GB --iterations 10
 # Running 'mem/memset' benchmark:
 # Copying 1GB Bytes ...

        2.086576 GB/Sec (with prefault)
 $ perf bench mem memset --only-prefault --length 1GB --iterations 100
 # Running 'mem/memset' benchmark:
 # Copying 1GB Bytes ...

      212.840917 MB/Sec (with prefault)

Fix this.

Signed-off-by: Rabin Vincent <rabin.vincent@axis.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Rabin Vincent <rabin@rab.in>
Cc: Rabin Vincent <rabinv@axis.com>
Link: http://lkml.kernel.org/r/1417535441-3965-3-git-send-email-rabin.vincent@axis.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 10 insertions, 8 deletions

diff --git a/tools/perf/bench/mem-memcpy.c b/tools/perf/bench/mem-memcpy.c
index e18be70c8a47..6c14afe8c1b1 100644
--- a/tools/perf/bench/mem-memcpy.c
+++ b/tools/perf/bench/mem-memcpy.c
@@ -141,6 +141,7 @@ static int bench_mem_common(int argc, const char **argv,
 {
         int i;
         size_t len;
+        double totallen;
         double result_bps[2];
         u64 result_cycle[2];
 
@@ -156,6 +157,7 @@ static int bench_mem_common(int argc, const char **argv,
                 init_cycle();
 
         len = (size_t)perf_atoll((char *)length_str);
+        totallen = (double)len * iterations;
 
         result_cycle[0] = result_cycle[1] = 0ULL;
         result_bps[0] = result_bps[1] = 0.0;
@@ -219,10 +221,10 @@ static int bench_mem_common(int argc, const char **argv,
                         if (use_cycle) {
                                 printf(" %14lf Cycle/Byte\n",
                                         (double)result_cycle[0]
-                                        / (double)len);
+                                        / totallen);
                                 printf(" %14lf Cycle/Byte (with prefault)\n",
                                         (double)result_cycle[1]
-                                        / (double)len);
+                                        / totallen);
                         } else {
                                 print_bps(result_bps[0]);
                                 printf("\n");
@@ -233,7 +235,7 @@ static int bench_mem_common(int argc, const char **argv,
                         if (use_cycle) {
                                 printf(" %14lf Cycle/Byte",
                                         (double)result_cycle[pf]
-                                        / (double)len);
+                                        / totallen);
                         } else
                                 print_bps(result_bps[pf]);
 
@@ -244,8 +246,8 @@ static int bench_mem_common(int argc, const char **argv,
                 if (!only_prefault && !no_prefault) {
                         if (use_cycle) {
                                 printf("%lf %lf\n",
-                                        (double)result_cycle[0] / (double)len,
-                                        (double)result_cycle[1] / (double)len);
+                                        (double)result_cycle[0] / totallen,
+                                        (double)result_cycle[1] / totallen);
                         } else {
                                 printf("%lf %lf\n",
                                         result_bps[0], result_bps[1]);
@@ -253,7 +255,7 @@ static int bench_mem_common(int argc, const char **argv,
                 } else {
                         if (use_cycle) {
                                 printf("%lf\n", (double)result_cycle[pf]
-                                        / (double)len);
+                                        / totallen);
                         } else
                                 printf("%lf\n", result_bps[pf]);
                 }
@@ -324,7 +326,7 @@ static double do_memcpy_gettimeofday(const struct routine *r, size_t len,
 
         free(src);
         free(dst);
-        return (double)((double)len / timeval2double(&tv_diff));
+        return (double)(((double)len * iterations) / timeval2double(&tv_diff));
 }
 
 int bench_mem_memcpy(int argc, const char **argv,
@@ -389,7 +391,7 @@ static double do_memset_gettimeofday(const struct routine *r, size_t len,
         timersub(&tv_end, &tv_start, &tv_diff);
 
         free(dst);
-        return (double)((double)len / timeval2double(&tv_diff));
+        return (double)(((double)len * iterations) / timeval2double(&tv_diff));
 }
 
 static const char * const bench_mem_memset_usage[] = {