perf bench: Allow passing an iteration count to "bench mem mem{cpy,set}"

"perf stat ... perf bench mem mem..." is pretty meaningless when using
small block sizes (as the overhead of the invocation of each test run
basically hides the actual test result in the noise). Repeating the
actually interesting function's invocation a number of times allows the
results to become meaningful.

Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/4F16D767020000780006D738@nat28.tlf.novell.com
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/bench/mem-memcpy.c b/tools/perf/bench/mem-memcpy.c
index db82021f4b91c7172a2fe43b4902e67f022af7b9..6ad2b1c6b27b1d5b1961963df14676939403e14b 100644 (file)
--- a/tools/perf/bench/mem-memcpy.c
+++ b/tools/perf/bench/mem-memcpy.c
@@ -24,6 +24,7 @@
 
 static const char      *length_str     = "1MB";
 static const char      *routine        = "default";
+static int             iterations      = 1;
 static bool            use_clock;
 static int             clock_fd;
 static bool            only_prefault;
@@ -35,6 +36,8 @@ static const struct option options[] = {
                    "available unit: B, MB, GB (upper and lower)"),
        OPT_STRING('r', "routine", &routine, "default",
                    "Specify routine to copy"),
+       OPT_INTEGER('i', "iterations", &iterations,
+                   "repeat memcpy() invocation this number of times"),
        OPT_BOOLEAN('c', "clock", &use_clock,
                    "Use CPU clock for measuring"),
        OPT_BOOLEAN('o', "only-prefault", &only_prefault,
@@ -121,6 +124,7 @@ static u64 do_memcpy_clock(memcpy_t fn, size_t len, bool prefault)
 {
        u64 clock_start = 0ULL, clock_end = 0ULL;
        void *src = NULL, *dst = NULL;
+       int i;
 
        alloc_mem(&src, &dst, len);
 
@@ -128,7 +132,8 @@ static u64 do_memcpy_clock(memcpy_t fn, size_t len, bool prefault)
                fn(dst, src, len);
 
        clock_start = get_clock();
-       fn(dst, src, len);
+       for (i = 0; i < iterations; ++i)
+               fn(dst, src, len);
        clock_end = get_clock();
 
        free(src);
@@ -140,6 +145,7 @@ static double do_memcpy_gettimeofday(memcpy_t fn, size_t len, bool prefault)
 {
        struct timeval tv_start, tv_end, tv_diff;
        void *src = NULL, *dst = NULL;
+       int i;
 
        alloc_mem(&src, &dst, len);
 
@@ -147,7 +153,8 @@ static double do_memcpy_gettimeofday(memcpy_t fn, size_t len, bool prefault)
                fn(dst, src, len);
 
        BUG_ON(gettimeofday(&tv_start, NULL));
-       fn(dst, src, len);
+       for (i = 0; i < iterations; ++i)
+               fn(dst, src, len);
        BUG_ON(gettimeofday(&tv_end, NULL));
 
        timersub(&tv_end, &tv_start, &tv_diff);

diff --git a/tools/perf/bench/mem-memset.c b/tools/perf/bench/mem-memset.c
index 9c0c6f0cba9b1e7b0a4863009669a70777ab96ad..59d4933eff4401b267392ae75c126bbeb9dacb83 100644 (file)
--- a/tools/perf/bench/mem-memset.c
+++ b/tools/perf/bench/mem-memset.c
@@ -24,6 +24,7 @@
 
 static const char      *length_str     = "1MB";
 static const char      *routine        = "default";
+static int             iterations      = 1;
 static bool            use_clock;
 static int             clock_fd;
 static bool            only_prefault;
@@ -35,6 +36,8 @@ static const struct option options[] = {
                    "available unit: B, MB, GB (upper and lower)"),
        OPT_STRING('r', "routine", &routine, "default",
                    "Specify routine to copy"),
+       OPT_INTEGER('i', "iterations", &iterations,
+                   "repeat memset() invocation this number of times"),
        OPT_BOOLEAN('c', "clock", &use_clock,
                    "Use CPU clock for measuring"),
        OPT_BOOLEAN('o', "only-prefault", &only_prefault,
@@ -117,6 +120,7 @@ static u64 do_memset_clock(memset_t fn, size_t len, bool prefault)
 {
        u64 clock_start = 0ULL, clock_end = 0ULL;
        void *dst = NULL;
+       int i;
 
        alloc_mem(&dst, len);
 
@@ -124,7 +128,8 @@ static u64 do_memset_clock(memset_t fn, size_t len, bool prefault)
                fn(dst, -1, len);
 
        clock_start = get_clock();
-       fn(dst, 0, len);
+       for (i = 0; i < iterations; ++i)
+               fn(dst, i, len);
        clock_end = get_clock();
 
        free(dst);
@@ -135,6 +140,7 @@ static double do_memset_gettimeofday(memset_t fn, size_t len, bool prefault)
 {
        struct timeval tv_start, tv_end, tv_diff;
        void *dst = NULL;
+       int i;
 
        alloc_mem(&dst, len);
 
@@ -142,7 +148,8 @@ static double do_memset_gettimeofday(memset_t fn, size_t len, bool prefault)
                fn(dst, -1, len);
 
        BUG_ON(gettimeofday(&tv_start, NULL));
-       fn(dst, 0, len);
+       for (i = 0; i < iterations; ++i)
+               fn(dst, i, len);
        BUG_ON(gettimeofday(&tv_end, NULL));
 
        timersub(&tv_end, &tv_start, &tv_diff);