[PATCH] selftest/powerpc: Add additional option to mmap_bench test

[Aneesh Kumar K.V]

This patch adds --pgfault and --iterations options to mmap_bench test. With
--pgfault we touch every page mapped. This helps in measuring impact in the
page fault path with a patch series.

Signed-off-by: Aneesh Kumar K.V <aneesh.ku...@linux.vnet.ibm.com>
---
 .../selftests/powerpc/benchmarks/mmap_bench.c      | 53 ++++++++++++++++++++--
 1 file changed, 50 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/powerpc/benchmarks/mmap_bench.c 
b/tools/testing/selftests/powerpc/benchmarks/mmap_bench.c
index 8d084a2d6e74..7a0a462a2272 100644
--- a/tools/testing/selftests/powerpc/benchmarks/mmap_bench.c
+++ b/tools/testing/selftests/powerpc/benchmarks/mmap_bench.c
@@ -7,17 +7,34 @@
 #include <stdlib.h>
 #include <sys/mman.h>
 #include <time.h>
+#include <getopt.h>
 
 #include "utils.h"
 
 #define ITERATIONS 5000000
 
-#define MEMSIZE (128 * 1024 * 1024)
+#define MEMSIZE (1UL << 27)
+#define PAGE_SIZE (1UL << 16)
+#define CHUNK_COUNT (MEMSIZE/PAGE_SIZE)
+
+static int pg_fault;
+static int iterations = ITERATIONS;
+
+static struct option options[] = {
+       { "pgfault", no_argument, &pg_fault, 1 },
+       { "iterations", required_argument, 0, 'i' },
+       { 0, },
+};
+
+static void usage(void)
+{
+       printf("mmap_bench <--pgfault> <--iterations count>\n");
+}
 
 int test_mmap(void)
 {
        struct timespec ts_start, ts_end;
-       unsigned long i = ITERATIONS;
+       unsigned long i = iterations;
 
        clock_gettime(CLOCK_MONOTONIC, &ts_start);
 
@@ -25,6 +42,11 @@ int test_mmap(void)
                char *c = mmap(NULL, MEMSIZE, PROT_READ|PROT_WRITE,
                               MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
                FAIL_IF(c == MAP_FAILED);
+               if (pg_fault) {
+                       int count;
+                       for (count = 0; count < CHUNK_COUNT; count++)
+                               c[count << 16] = 'c';
+               }
                munmap(c, MEMSIZE);
        }
 
@@ -35,7 +57,32 @@ int test_mmap(void)
        return 0;
 }
 
-int main(void)
+int main(int argc, char *argv[])
 {
+       signed char c;
+       while (1) {
+               int option_index = 0;
+
+               c = getopt_long(argc, argv, "", options, &option_index);
+
+               if (c == -1)
+                       break;
+
+               switch (c) {
+               case 0:
+                       if (options[option_index].flag != 0)
+                               break;
+
+                       usage();
+                       exit(1);
+                       break;
+               case 'i':
+                       iterations = atoi(optarg);
+                       break;
+               default:
+                       usage();
+                       exit(1);
+               }
+       }
        return test_harness(test_mmap, "mmap_bench");
 }
-- 
2.14.3