[PATCH 03/23] perf bench: Improve the 'perf bench mem memcpy' code readability

From: Arnaldo Carvalho de Melo
Date: Mon Oct 19 2015 - 17:41:09 EST


From: Ingo Molnar <mingo@xxxxxxxxxx>

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

Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: David Ahern <dsahern@xxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/1445241870-24854-2-git-send-email-mingo@xxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
tools/perf/bench/mem-memcpy.c | 101 +++++++++++++++++++-----------------------
1 file changed, 45 insertions(+), 56 deletions(-)

diff --git a/tools/perf/bench/mem-memcpy.c b/tools/perf/bench/mem-memcpy.c
index d3dfb7936dcd..27606ff5c4f9 100644
--- a/tools/perf/bench/mem-memcpy.c
+++ b/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@xxxxxxxxxxxxxxxxxxxxx>
*/
@@ -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);
--
2.1.0

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