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>

diff --git a/tools/perf/bench/mem-memcpy.c b/tools/perf/bench/mem-memcpy.c
index d3dfb7936dcdfd688d20ae680b3b0c0009cdeb55..27606ff5c4f9a8c6d169cb9411649543f2231d1a 100644 (file)
--- 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@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);