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Commit 12eac0bf authored by Hitoshi Mitake's avatar Hitoshi Mitake Committed by Ingo Molnar
Browse files

perf bench: Make the mem/memcpy tests more user-friendly 



mem-memcpy.c uses perf event system calls to obtain CPU clocks.
And it suddenly dies with BUG_ON() when it running on Linux
doesn't support perf event.

Also fail at calloc() can occur easily when too large
length is passed. Fail of calloc() causes sudden death
with assert().

These behaviours are not friendly. So I fixed the treating of
errors.

Signed-off-by: default avatarHitoshi Mitake <mitake@dcl.info.waseda.ac.jp>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <1258688237-3797-1-git-send-email-mitake@dcl.info.waseda.ac.jp>
[ v2: improved a few small details ]
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 827f3b49

tools/perf/bench/mem-memcpy.c

+22 −15
Original line number Diff line number Diff line
@@ -25,6 +25,7 @@ 
static const char	*length_str	= "1MB";

static const char	*routine	= "default";

static int		use_clock	= 0;

static int		clock_fd;



static const struct option options[] = {

	OPT_STRING('l', "length", &length_str, "1MB",
@@ -57,8 +58,6 @@ static const char * const bench_mem_memcpy_usage[] = { 
	NULL

};



static int clock_fd;



static struct perf_event_attr clock_attr = {

	.type		= PERF_TYPE_HARDWARE,

	.config		= PERF_COUNT_HW_CPU_CYCLES
@@ -67,6 +66,10 @@ static struct perf_event_attr clock_attr = { 
static void init_clock(void)

{

	clock_fd = sys_perf_event_open(&clock_attr, getpid(), -1, -1, 0);



	if (clock_fd < 0 && errno == ENOSYS)

		die("No CONFIG_PERF_EVENTS=y kernel support configured?\n");

	else

		BUG_ON(clock_fd < 0);

}
@@ -104,7 +107,8 @@ int bench_mem_memcpy(int argc, const char **argv, 
	tv_diff.tv_sec = 0;

	tv_diff.tv_usec = 0;

	length = (size_t)perf_atoll((char *)length_str);

	if ((long long int)length <= 0) {



	if ((s64)length <= 0) {

		fprintf(stderr, "Invalid length:%s\n", length_str);

		return 1;

	}
@@ -124,9 +128,12 @@ int bench_mem_memcpy(int argc, const char **argv, 
	}



	dst = calloc(length, sizeof(char));

	assert(dst);

	if (!dst)

		die("memory allocation failed - maybe length is too large?\n");



	src = calloc(length, sizeof(char));

	assert(src);

	if (!src)

		die("memory allocation failed - maybe length is too large?\n");



	if (bench_format == BENCH_FORMAT_DEFAULT) {

		printf("# Copying %s Bytes from %p to %p ...\n\n",
@@ -136,8 +143,9 @@ int bench_mem_memcpy(int argc, const char **argv, 
	if (use_clock) {

		init_clock();

		clock_start = get_clock();

	} else

	} else {

		BUG_ON(gettimeofday(&tv_start, NULL));

	}



	routines[i].fn(dst, src, length);
@@ -176,9 +184,8 @@ int bench_mem_memcpy(int argc, const char **argv, 
			printf("%lf\n", bps);

		break;

	default:

		/* reaching here is something disaster */

		fprintf(stderr, "Unknown format:%d\n", bench_format);

		exit(1);

		/* reaching this means there's some disaster: */

		die("unknown format: %d\n", bench_format);

		break;

	}