perf bench: Improve the 'perf bench mem memcpy' code readability

 - improve the readability of initializations
 - fix unnecessary double negations
 - fix ugly line breaks
 - fix other small details

Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1445241870-24854-2-git-send-email-mingo@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/bench/mem-memcpy.c

@@ -1,7 +1,7 @@
 /*
  * mem-memcpy.c
  *
- * memcpy: Simple memory copy in various ways
+ * Simple memcpy() and memset() benchmarks
  *
  * Written by Hitoshi Mitake <mitake@dcl.info.waseda.ac.jp>
  */
@@ -61,20 +61,17 @@ struct routine {
 };
 
 struct routine memcpy_routines[] = {
-	{ .name = "default",
-	  .desc = "Default memcpy() provided by glibc",
-	  .fn.memcpy = memcpy },
-#ifdef HAVE_ARCH_X86_64_SUPPORT
-
-#define MEMCPY_FN(_fn, _name, _desc) {.name = _name, .desc = _desc, .fn.memcpy = _fn},
-#include "mem-memcpy-x86-64-asm-def.h"
-#undef MEMCPY_FN
+	{ .name		= "default",
+	  .desc		= "Default memcpy() provided by glibc",
+	  .fn.memcpy	= memcpy },
 
+#ifdef HAVE_ARCH_X86_64_SUPPORT
+# define MEMCPY_FN(_fn, _name, _desc) {.name = _name, .desc = _desc, .fn.memcpy = _fn},
+# include "mem-memcpy-x86-64-asm-def.h"
+# undef MEMCPY_FN
 #endif
 
-	{ NULL,
-	  NULL,
-	  {NULL}   }
+	{ NULL, }
 };
 
 static const char * const bench_mem_memcpy_usage[] = {
@@ -89,8 +86,7 @@ static struct perf_event_attr cycle_attr = {
 
 static void init_cycle(void)
 {
-	cycle_fd = sys_perf_event_open(&cycle_attr, getpid(), -1, -1,
-				       perf_event_open_cloexec_flag());
+	cycle_fd = sys_perf_event_open(&cycle_attr, getpid(), -1, -1, perf_event_open_cloexec_flag());
 
 	if (cycle_fd < 0 && errno == ENOSYS)
 		die("No CONFIG_PERF_EVENTS=y kernel support configured?\n");
@@ -111,12 +107,9 @@ static u64 get_cycle(void)
 
 static double timeval2double(struct timeval *ts)
 {
-	return (double)ts->tv_sec +
-		(double)ts->tv_usec / (double)1000000;
+	return (double)ts->tv_sec + (double)ts->tv_usec / (double)1000000;
 }
 
-#define pf (no_prefault ? 0 : 1)
-
 #define print_bps(x) do {					\
 		if (x < K)					\
 			printf(" %14lf B/Sec", x);		\
@@ -140,6 +133,7 @@ static void __bench_mem_routine(struct bench_mem_info *info, int r_idx, size_t l
 	const struct routine *r = &info->routines[r_idx];
 	double result_bps[2];
 	u64 result_cycle[2];
+	int prefault = no_prefault ? 0 : 1;
 
 	result_cycle[0] = result_cycle[1] = 0ULL;
 	result_bps[0] = result_bps[1] = 0.0;
@@ -149,8 +143,8 @@ static void __bench_mem_routine(struct bench_mem_info *info, int r_idx, size_t l
 	if (bench_format == BENCH_FORMAT_DEFAULT)
 		printf("# Copying %s Bytes ...\n\n", length_str);
 
-	if (!only_prefault && !no_prefault) {
-		/* show both of results */
+	if (!only_prefault && prefault) {
+		/* Show both results: */
 		if (use_cycle) {
 			result_cycle[0] = info->do_cycle(r, len, false);
 			result_cycle[1] = info->do_cycle(r, len, true);
@@ -160,14 +154,14 @@ static void __bench_mem_routine(struct bench_mem_info *info, int r_idx, size_t l
 		}
 	} else {
 		if (use_cycle)
-			result_cycle[pf] = info->do_cycle(r, len, only_prefault);
+			result_cycle[prefault] = info->do_cycle(r, len, only_prefault);
 		else
-			result_bps[pf] = info->do_gettimeofday(r, len, only_prefault);
+			result_bps[prefault] = info->do_gettimeofday(r, len, only_prefault);
 	}
 
 	switch (bench_format) {
 	case BENCH_FORMAT_DEFAULT:
-		if (!only_prefault && !no_prefault) {
+		if (!only_prefault && prefault) {
 			if (use_cycle) {
 				printf(" %14lf Cycle/Byte\n",
 					(double)result_cycle[0]
@@ -184,16 +178,16 @@ static void __bench_mem_routine(struct bench_mem_info *info, int r_idx, size_t l
 		} else {
 			if (use_cycle) {
 				printf(" %14lf Cycle/Byte",
-					(double)result_cycle[pf]
+					(double)result_cycle[prefault]
 					/ totallen);
 			} else
-				print_bps(result_bps[pf]);
+				print_bps(result_bps[prefault]);
 
 			printf("%s\n", only_prefault ? " (with prefault)" : "");
 		}
 		break;
 	case BENCH_FORMAT_SIMPLE:
-		if (!only_prefault && !no_prefault) {
+		if (!only_prefault && prefault) {
 			if (use_cycle) {
 				printf("%lf %lf\n",
 					(double)result_cycle[0] / totallen,
@@ -204,14 +198,14 @@ static void __bench_mem_routine(struct bench_mem_info *info, int r_idx, size_t l
 			}
 		} else {
 			if (use_cycle) {
-				printf("%lf\n", (double)result_cycle[pf]
+				printf("%lf\n", (double)result_cycle[prefault]
 					/ totallen);
 			} else
-				printf("%lf\n", result_bps[pf]);
+				printf("%lf\n", result_bps[prefault]);
 		}
 		break;
 	default:
-		/* reaching this means there's some disaster: */
+		/* Reaching this means there's some disaster: */
 		die("unknown format: %d\n", bench_format);
 		break;
 	}
@@ -225,8 +219,7 @@ static int bench_mem_common(int argc, const char **argv,
 	size_t len;
 	double totallen;
 
-	argc = parse_options(argc, argv, options,
-			     info->usage, 0);
+	argc = parse_options(argc, argv, options, info->usage, 0);
 
 	if (no_prefault && only_prefault) {
 		fprintf(stderr, "Invalid options: -o and -n are mutually exclusive\n");
@@ -244,7 +237,7 @@ static int bench_mem_common(int argc, const char **argv,
 		return 1;
 	}
 
-	/* same to without specifying either of prefault and no-prefault */
+	/* Same as without specifying either of prefault and no-prefault: */
 	if (only_prefault && no_prefault)
 		only_prefault = no_prefault = false;
 
@@ -282,7 +275,8 @@ static void memcpy_alloc_mem(void **dst, void **src, size_t length)
 	*src = zalloc(length);
 	if (!*src)
 		die("memory allocation failed - maybe length is too large?\n");
-	/* Make sure to always replace the zero pages even if MMAP_THRESH is crossed */
+
+	/* Make sure to always prefault zero pages even if MMAP_THRESH is crossed: */
 	memset(*src, 0, length);
 }
 
@@ -308,8 +302,7 @@ static u64 do_memcpy_cycle(const struct routine *r, size_t len, bool prefault)
 	return cycle_end - cycle_start;
 }
 
-static double do_memcpy_gettimeofday(const struct routine *r, size_t len,
-				     bool prefault)
+static double do_memcpy_gettimeofday(const struct routine *r, size_t len, bool prefault)
 {
 	struct timeval tv_start, tv_end, tv_diff;
 	memcpy_t fn = r->fn.memcpy;
@@ -337,10 +330,10 @@ int bench_mem_memcpy(int argc, const char **argv,
 		     const char *prefix __maybe_unused)
 {
 	struct bench_mem_info info = {
-		.routines = memcpy_routines,
-		.do_cycle = do_memcpy_cycle,
-		.do_gettimeofday = do_memcpy_gettimeofday,
-		.usage = bench_mem_memcpy_usage,
+		.routines		= memcpy_routines,
+		.do_cycle		= do_memcpy_cycle,
+		.do_gettimeofday	= do_memcpy_gettimeofday,
+		.usage			= bench_mem_memcpy_usage,
 	};
 
 	return bench_mem_common(argc, argv, prefix, &info);
@@ -404,30 +397,26 @@ static const char * const bench_mem_memset_usage[] = {
 };
 
 static const struct routine memset_routines[] = {
-	{ .name ="default",
-	  .desc = "Default memset() provided by glibc",
-	  .fn.memset = memset },
-#ifdef HAVE_ARCH_X86_64_SUPPORT
-
-#define MEMSET_FN(_fn, _name, _desc) { .name = _name, .desc = _desc, .fn.memset = _fn },
-#include "mem-memset-x86-64-asm-def.h"
-#undef MEMSET_FN
+	{ .name		= "default",
+	  .desc		= "Default memset() provided by glibc",
+	  .fn.memset	= memset },
 
+#ifdef HAVE_ARCH_X86_64_SUPPORT
+# define MEMSET_FN(_fn, _name, _desc) { .name = _name, .desc = _desc, .fn.memset = _fn },
+# include "mem-memset-x86-64-asm-def.h"
+# undef MEMSET_FN
 #endif
 
-	{ .name = NULL,
-	  .desc = NULL,
-	  .fn.memset = NULL   }
+	{ NULL, }
 };
 
-int bench_mem_memset(int argc, const char **argv,
-		     const char *prefix __maybe_unused)
+int bench_mem_memset(int argc, const char **argv, const char *prefix __maybe_unused)
 {
 	struct bench_mem_info info = {
-		.routines = memset_routines,
-		.do_cycle = do_memset_cycle,
-		.do_gettimeofday = do_memset_gettimeofday,
-		.usage = bench_mem_memset_usage,
+		.routines		= memset_routines,
+		.do_cycle		= do_memset_cycle,
+		.do_gettimeofday	= do_memset_gettimeofday,
+		.usage			= bench_mem_memset_usage,
 	};
 
 	return bench_mem_common(argc, argv, prefix, &info);