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Subject[PATCH 05/17] perf ftrace: Add support for -a and -C option
Date
From: Namhyung Kim <namhyung.kim@lge.com>

The -a/--all-cpus and -C/--cpu option is for controlling tracing cpus.
To do that, add and use cpu_map__sprintf() function.

Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
---
tools/perf/builtin-ftrace.c | 69 +++++++++++++++++++++++++++++++++++++++++++++
tools/perf/util/cpumap.c | 45 +++++++++++++++++++++++++++++
tools/perf/util/cpumap.h | 1 +
3 files changed, 115 insertions(+)

diff --git a/tools/perf/builtin-ftrace.c b/tools/perf/builtin-ftrace.c
index bd415f2b1cde..642aa49c66d7 100644
--- a/tools/perf/builtin-ftrace.c
+++ b/tools/perf/builtin-ftrace.c
@@ -18,6 +18,7 @@
#include "util/evlist.h"
#include "util/target.h"
#include "util/thread_map.h"
+#include "util/cpumap.h"


#define DEFAULT_TRACER "function_graph"
@@ -80,6 +81,8 @@ static int append_tracing_file(const char *name, const char *val)
return __write_tracing_file(name, val, true);
}

+static int reset_tracing_cpu(void);
+
static int reset_tracing_files(struct perf_ftrace *ftrace __maybe_unused)
{
if (write_tracing_file("tracing_on", "0") < 0)
@@ -91,6 +94,9 @@ static int reset_tracing_files(struct perf_ftrace *ftrace __maybe_unused)
if (write_tracing_file("set_ftrace_pid", " ") < 0)
return -1;

+ if (reset_tracing_cpu() < 0)
+ return -1;
+
return 0;
}

@@ -111,6 +117,60 @@ static int set_tracing_pid(struct perf_ftrace *ftrace)
return 0;
}

+static int set_tracing_cpu(struct perf_ftrace *ftrace)
+{
+ char *cpumask;
+ size_t mask_size;
+ int ret;
+ int last_cpu;
+ struct cpu_map *cpumap = ftrace->evlist->cpus;
+
+ if (!perf_target__has_cpu(&ftrace->target))
+ return 0;
+
+ last_cpu = cpumap->map[cpumap->nr - 1];
+ mask_size = (last_cpu + 3) / 4 + 1;
+ mask_size += last_cpu / 32; /* ',' is needed for every 32th cpus */
+
+ cpumask = malloc(mask_size);
+ if (cpumask == NULL) {
+ pr_debug("failed to allocate cpu mask\n");
+ return -1;
+ }
+
+ cpu_map__sprintf(cpumap, cpumask);
+
+ ret = write_tracing_file("tracing_cpumask", cpumask);
+
+ free(cpumask);
+ return ret;
+}
+
+static int reset_tracing_cpu(void)
+{
+ char *cpumask;
+ size_t mask_size;
+ int last_cpu;
+ struct cpu_map *cpumap = cpu_map__new(NULL);
+
+ last_cpu = cpumap->map[cpumap->nr - 1];
+ mask_size = (last_cpu + 3) / 4 + 1;
+ mask_size += last_cpu / 32; /* ',' is needed for every 32th cpus */
+
+ cpumask = malloc(mask_size);
+ if (cpumask == NULL) {
+ pr_debug("failed to allocate cpu mask\n");
+ return -1;
+ }
+
+ cpu_map__sprintf(cpumap, cpumask);
+
+ write_tracing_file("tracing_cpumask", cpumask);
+
+ free(cpumask);
+ return 0;
+}
+
static int __cmd_ftrace(struct perf_ftrace *ftrace, int argc, const char **argv)
{
char *trace_file;
@@ -147,6 +207,11 @@ static int __cmd_ftrace(struct perf_ftrace *ftrace, int argc, const char **argv)
goto out_reset;
}

+ if (set_tracing_cpu(ftrace) < 0) {
+ pr_err("failed to set tracing cpumask\n");
+ goto out_reset;
+ }
+
if (write_tracing_file("current_tracer", ftrace->tracer) < 0) {
pr_err("failed to set current_tracer to %s\n", ftrace->tracer);
goto out_reset;
@@ -227,6 +292,10 @@ int cmd_ftrace(int argc, const char **argv, const char *prefix __maybe_unused)
"trace on existing process id"),
OPT_INCR('v', "verbose", &verbose,
"be more verbose"),
+ OPT_BOOLEAN('a', "all-cpus", &ftrace.target.system_wide,
+ "system-wide collection from all CPUs"),
+ OPT_STRING('C', "cpu", &ftrace.target.cpu_list, "cpu",
+ "list of cpus to monitor"),
OPT_END()
};

diff --git a/tools/perf/util/cpumap.c b/tools/perf/util/cpumap.c
index beb8cf9f9976..7933839915ea 100644
--- a/tools/perf/util/cpumap.c
+++ b/tools/perf/util/cpumap.c
@@ -187,6 +187,51 @@ size_t cpu_map__fprintf(struct cpu_map *map, FILE *fp)
return printed + fprintf(fp, "\n");
}

+static char hex_char(char val)
+{
+ if (0 <= val && val <= 9)
+ return val + '0';
+ if (10 <= val && val < 16)
+ return val - 10 + 'a';
+ return '?';
+}
+
+size_t cpu_map__sprintf(struct cpu_map *map, char *buf)
+{
+ int i, cpu;
+ char *ptr = buf;
+ unsigned char *bitmap;
+ int last_cpu = map->map[map->nr - 1];
+
+ bitmap = zalloc((last_cpu + 7) / 8);
+ if (bitmap == NULL) {
+ buf[0] = '\0';
+ return 0;
+ }
+
+ for (i = 0; i < map->nr; i++) {
+ cpu = map->map[i];
+ bitmap[cpu / 8] |= 1 << (cpu % 8);
+ }
+
+ for (cpu = last_cpu / 4 * 4; cpu >= 0; cpu -= 4) {
+ unsigned char bits = bitmap[cpu / 8];
+
+ if (cpu % 8)
+ bits >>= 4;
+ else
+ bits &= 0xf;
+
+ *ptr++ = hex_char(bits);
+ if ((cpu % 32) == 0 && cpu > 0)
+ *ptr++ = ',';
+ }
+ *ptr++ = '\0';
+
+ free(bitmap);
+ return ptr - buf;
+}
+
struct cpu_map *cpu_map__dummy_new(void)
{
struct cpu_map *cpus = malloc(sizeof(*cpus) + sizeof(int));
diff --git a/tools/perf/util/cpumap.h b/tools/perf/util/cpumap.h
index b123bb9d6f55..a9a7f19f89d7 100644
--- a/tools/perf/util/cpumap.h
+++ b/tools/perf/util/cpumap.h
@@ -14,6 +14,7 @@ struct cpu_map *cpu_map__dummy_new(void);
void cpu_map__delete(struct cpu_map *map);
struct cpu_map *cpu_map__read(FILE *file);
size_t cpu_map__fprintf(struct cpu_map *map, FILE *fp);
+size_t cpu_map__sprintf(struct cpu_map *map, char *buf);
int cpu_map__get_socket(struct cpu_map *map, int idx);
int cpu_map__get_core(struct cpu_map *map, int idx);
int cpu_map__build_socket_map(struct cpu_map *cpus, struct cpu_map **sockp);
--
1.7.11.7


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