perf events: Change perf parameter --pid to process-wide collection instead of thread-wide

Parameter --pid (or -p) of perf currently means a thread-wide
collection. For exmaple, if a process whose id is 8888 has 10
threads, 'perf top -p 8888' just collects the main thread
statistics. That's misleading. Users are used to attach a whole
process when debugging a process by gdb. To follow normal usage
style, the patch change --pid to process-wide collection and add
--tid (-t) to mean a thread-wide collection.

Usage example is:

 # perf top -p 8888
 # perf record -p 8888 -f sleep 10
 # perf stat -p 8888 -f sleep 10

Above commands collect the statistics of all threads of process
8888.

Signed-off-by: Zhang Yanmin <yanmin_zhang@linux.intel.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Avi Kivity <avi@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Sheng Yang <sheng@linux.intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Jes Sorensen <Jes.Sorensen@redhat.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Gleb Natapov <gleb@redhat.com>
Cc: zhiteng.huang@intel.com
Cc: Zachary Amsden <zamsden@redhat.com>
LKML-Reference: <1268922965-14774-3-git-send-email-acme@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 75 insertions, 35 deletions

diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index 5f41244cbbf..c92f90ff5a9 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -46,6 +46,7 @@
 #include "util/debug.h"
 #include "util/header.h"
 #include "util/cpumap.h"
+#include "util/thread.h"
 
 #include <sys/prctl.h>
 #include <math.h>
@@ -74,10 +75,13 @@ static int			run_count			=  1;
 static int			inherit				=  1;
 static int			scale				=  1;
 static pid_t			target_pid			= -1;
+static pid_t			target_tid			= -1;
+static pid_t			*all_tids			=  NULL;
+static int			thread_num			=  0;
 static pid_t			child_pid			= -1;
 static int			null_run			=  0;
 
-static int			fd[MAX_NR_CPUS][MAX_COUNTERS];
+static int			*fd[MAX_NR_CPUS][MAX_COUNTERS];
 
 static int			event_scaled[MAX_COUNTERS];
 
@@ -140,9 +144,10 @@ struct stats			runtime_branches_stats;
 #define ERR_PERF_OPEN \
 "Error: counter %d, sys_perf_event_open() syscall returned with %d (%s)\n"
 
-static void create_perf_stat_counter(int counter, int pid)
+static void create_perf_stat_counter(int counter)
 {
 	struct perf_event_attr *attr = attrs + counter;
+	int thread;
 
 	if (scale)
 		attr->read_format = PERF_FORMAT_TOTAL_TIME_ENABLED |
@@ -152,10 +157,11 @@ static void create_perf_stat_counter(int counter, int pid)
 		unsigned int cpu;
 
 		for (cpu = 0; cpu < nr_cpus; cpu++) {
-			fd[cpu][counter] = sys_perf_event_open(attr, -1, cpumap[cpu], -1, 0);
-			if (fd[cpu][counter] < 0 && verbose)
+			fd[cpu][counter][0] = sys_perf_event_open(attr,
+					-1, cpumap[cpu], -1, 0);
+			if (fd[cpu][counter][0] < 0 && verbose)
 				fprintf(stderr, ERR_PERF_OPEN, counter,
-					fd[cpu][counter], strerror(errno));
+					fd[cpu][counter][0], strerror(errno));
 		}
 	} else {
 		attr->inherit	     = inherit;
@@ -163,11 +169,14 @@ static void create_perf_stat_counter(int counter, int pid)
 			attr->disabled = 1;
 			attr->enable_on_exec = 1;
 		}
-
-		fd[0][counter] = sys_perf_event_open(attr, pid, -1, -1, 0);
-		if (fd[0][counter] < 0 && verbose)
-			fprintf(stderr, ERR_PERF_OPEN, counter,
-				fd[0][counter], strerror(errno));
+		for (thread = 0; thread < thread_num; thread++) {
+			fd[0][counter][thread] = sys_perf_event_open(attr,
+				all_tids[thread], -1, -1, 0);
+			if (fd[0][counter][thread] < 0 && verbose)
+				fprintf(stderr, ERR_PERF_OPEN, counter,
+					fd[0][counter][thread],
+					strerror(errno));
+		}
 	}
 }
 
@@ -192,25 +201,28 @@ static void read_counter(int counter)
 	unsigned int cpu;
 	size_t res, nv;
 	int scaled;
-	int i;
+	int i, thread;
 
 	count[0] = count[1] = count[2] = 0;
 
 	nv = scale ? 3 : 1;
 	for (cpu = 0; cpu < nr_cpus; cpu++) {
-		if (fd[cpu][counter] < 0)
-			continue;
-
-		res = read(fd[cpu][counter], single_count, nv * sizeof(u64));
-		assert(res == nv * sizeof(u64));
-
-		close(fd[cpu][counter]);
-		fd[cpu][counter] = -1;
-
-		count[0] += single_count[0];
-		if (scale) {
-			count[1] += single_count[1];
-			count[2] += single_count[2];
+		for (thread = 0; thread < thread_num; thread++) {
+			if (fd[cpu][counter][thread] < 0)
+				continue;
+
+			res = read(fd[cpu][counter][thread],
+					single_count, nv * sizeof(u64));
+			assert(res == nv * sizeof(u64));
+
+			close(fd[cpu][counter][thread]);
+			fd[cpu][counter][thread] = -1;
+
+			count[0] += single_count[0];
+			if (scale) {
+				count[1] += single_count[1];
+				count[2] += single_count[2];
+			}
 		}
 	}
 
@@ -253,7 +265,6 @@ static int run_perf_stat(int argc __used, const char **argv)
 	unsigned long long t0, t1;
 	int status = 0;
 	int counter;
-	int pid;
 	int child_ready_pipe[2], go_pipe[2];
 	const bool forks = (argc > 0);
 	char buf;
@@ -299,6 +310,9 @@ static int run_perf_stat(int argc __used, const char **argv)
 			exit(-1);
 		}
 
+		if (target_tid == -1 && target_pid == -1 && !system_wide)
+			all_tids[0] = child_pid;
+
 		/*
 		 * Wait for the child to be ready to exec.
 		 */
@@ -309,12 +323,8 @@ static int run_perf_stat(int argc __used, const char **argv)
 		close(child_ready_pipe[0]);
 	}
 
-	if (target_pid == -1)
-		pid = child_pid;
-	else
-		pid = target_pid;
 	for (counter = 0; counter < nr_counters; counter++)
-		create_perf_stat_counter(counter, pid);
+		create_perf_stat_counter(counter);
 
 	/*
 	 * Enable counters and exec the command:
@@ -433,12 +443,14 @@ static void print_stat(int argc, const char **argv)
 
 	fprintf(stderr, "\n");
 	fprintf(stderr, " Performance counter stats for ");
-	if(target_pid == -1) {
+	if(target_pid == -1 && target_tid == -1) {
 		fprintf(stderr, "\'%s", argv[0]);
 		for (i = 1; i < argc; i++)
 			fprintf(stderr, " %s", argv[i]);
-	}else
-		fprintf(stderr, "task pid \'%d", target_pid);
+	} else if (target_pid != -1)
+		fprintf(stderr, "process id \'%d", target_pid);
+	else
+		fprintf(stderr, "thread id \'%d", target_tid);
 
 	fprintf(stderr, "\'");
 	if (run_count > 1)
@@ -493,7 +505,9 @@ static const struct option options[] = {
 	OPT_BOOLEAN('i', "inherit", &inherit,
 		    "child tasks inherit counters"),
 	OPT_INTEGER('p', "pid", &target_pid,
-		    "stat events on existing pid"),
+		    "stat events on existing process id"),
+	OPT_INTEGER('t', "tid", &target_tid,
+		    "stat events on existing thread id"),
 	OPT_BOOLEAN('a', "all-cpus", &system_wide,
 		    "system-wide collection from all CPUs"),
 	OPT_BOOLEAN('c', "scale", &scale,
@@ -510,10 +524,11 @@ static const struct option options[] = {
 int cmd_stat(int argc, const char **argv, const char *prefix __used)
 {
 	int status;
+	int i,j;
 
 	argc = parse_options(argc, argv, options, stat_usage,
 		PARSE_OPT_STOP_AT_NON_OPTION);
-	if (!argc && target_pid == -1)
+	if (!argc && target_pid == -1 && target_tid == -1)
 		usage_with_options(stat_usage, options);
 	if (run_count <= 0)
 		usage_with_options(stat_usage, options);
@@ -529,6 +544,31 @@ int cmd_stat(int argc, const char **argv, const char *prefix __used)
 	else
 		nr_cpus = 1;
 
+	if (target_pid != -1) {
+		target_tid = target_pid;
+		thread_num = find_all_tid(target_pid, &all_tids);
+		if (thread_num <= 0) {
+			fprintf(stderr, "Can't find all threads of pid %d\n",
+					target_pid);
+			usage_with_options(stat_usage, options);
+		}
+	} else {
+		all_tids=malloc(sizeof(pid_t));
+		if (!all_tids)
+			return -ENOMEM;
+
+		all_tids[0] = target_tid;
+		thread_num = 1;
+	}
+
+	for (i = 0; i < MAX_NR_CPUS; i++) {
+		for (j = 0; j < MAX_COUNTERS; j++) {
+			fd[i][j] = malloc(sizeof(int)*thread_num);
+			if (!fd[i][j])
+				return -ENOMEM;
+		}
+	}
+
 	/*
 	 * We dont want to block the signals - that would cause
 	 * child tasks to inherit that and Ctrl-C would not work.