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>
diff --git a/tools/perf/util/thread.c b/tools/perf/util/thread.c
index fa96831..ea65062 100644
--- a/tools/perf/util/thread.c
+++ b/tools/perf/util/thread.c
@@ -7,6 +7,37 @@
#include "util.h"
#include "debug.h"
+int find_all_tid(int pid, pid_t ** all_tid)
+{
+ char name[256];
+ int items;
+ struct dirent **namelist = NULL;
+ int ret = 0;
+ int i;
+
+ sprintf(name, "/proc/%d/task", pid);
+ items = scandir(name, &namelist, NULL, NULL);
+ if (items <= 0)
+ return -ENOENT;
+ *all_tid = malloc(sizeof(pid_t) * items);
+ if (!*all_tid) {
+ ret = -ENOMEM;
+ goto failure;
+ }
+
+ for (i = 0; i < items; i++)
+ (*all_tid)[i] = atoi(namelist[i]->d_name);
+
+ ret = items;
+
+failure:
+ for (i=0; i<items; i++)
+ free(namelist[i]);
+ free(namelist);
+
+ return ret;
+}
+
void map_groups__init(struct map_groups *self)
{
int i;
@@ -348,3 +379,4 @@
return NULL;
}
+