taskstats: add context-switch counters
Make available to the user the following task and process performance
statistics:
* Involuntary Context Switches (task_struct->nivcsw)
* Voluntary Context Switches (task_struct->nvcsw)
Statistics information is available from:
1. taskstats interface (Documentation/accounting/)
2. /proc/PID/status (task only).
This data is useful for detecting hyperactivity patterns between processes.
[akpm@linux-foundation.org: cleanup]
Signed-off-by: Maxim Uvarov <muvarov@ru.mvista.com>
Cc: Shailabh Nagar <nagar@watson.ibm.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Jay Lan <jlan@engr.sgi.com>
Cc: Jonathan Lim <jlim@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/proc/array.c b/fs/proc/array.c
index 680c913..9cbab7e 100644
--- a/fs/proc/array.c
+++ b/fs/proc/array.c
@@ -289,6 +289,15 @@
cap_t(p->cap_effective));
}
+static inline char *task_context_switch_counts(struct task_struct *p,
+ char *buffer)
+{
+ return buffer + sprintf(buffer, "voluntary_ctxt_switches:\t%lu\n"
+ "nonvoluntary_ctxt_switches:\t%lu\n",
+ p->nvcsw,
+ p->nivcsw);
+}
+
int proc_pid_status(struct task_struct *task, char * buffer)
{
char * orig = buffer;
@@ -307,6 +316,7 @@
#if defined(CONFIG_S390)
buffer = task_show_regs(task, buffer);
#endif
+ buffer = task_context_switch_counts(task, buffer);
return buffer - orig;
}