[RFC][PATCH -mm 2/3] Freezer: Measure the time of freezing tasks

Rafael J. Wysocki
2007-07-31T22:28:43Z

From: Rafael J. Wysocki <rjw@sisk.pl>

Measure the time of the freezing of tasks, even if it doesn't fail.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
---
kernel/power/process.c | 18 +++++++++++++++---
1 file changed, 15 insertions(+), 3 deletions(-)
---
Index: linux-2.6.23-rc1/kernel/power/process.c
===================================================================
--- linux-2.6.23-rc1.orig/kernel/power/process.c 2007-07-31 23:00:43.000000000 +0200
+++ linux-2.6.23-rc1/kernel/power/process.c 2007-07-31 23:00:52.000000000 +0200
@@ -190,6 +190,11 @@ static int try_to_freeze_tasks(int freez
struct task_struct *g, *p;
unsigned long end_time;
unsigned int todo;
+ struct timeval start, end;
+ s64 elapsed_csecs64;
+ unsigned int elapsed_csecs;
+
+ do_gettimeofday(&start);

end_time = jiffies + TIMEOUT;
refrigerator_called = 0;
@@ -226,6 +231,11 @@ static int try_to_freeze_tasks(int freez
break;
} while (todo);

+ do_gettimeofday(&end);
+ elapsed_csecs64 = timeval_to_ns(&end) - timeval_to_ns(&start);
+ do_div(elapsed_csecs64, NSEC_PER_SEC / 100);
+ elapsed_csecs = elapsed_csecs64;
+
if (todo) {
/* This does not unfreeze processes that are already frozen
* (we have slightly ugly calling convention in that respect,
@@ -233,10 +243,9 @@ static int try_to_freeze_tasks(int freez
* but it cleans up leftover PF_FREEZE requests.
*/
printk("\n");
- printk(KERN_ERR "Freezing of %s timed out after %d seconds "
+ printk(KERN_ERR "Freezing of tasks failed after %d.%d seconds "
"(%d tasks refusing to freeze):\n",
- freeze_user_space ? "user space " : "tasks ",
- TIMEOUT / HZ, todo);
+ elapsed_csecs / 100, elapsed_csecs % 100, todo);
show_state();
read_lock(&tasklist_lock);
do_each_thread(g, p) {
@@ -247,6 +256,9 @@ static int try_to_freeze_tasks(int freez
task_unlock(p);
} while_each_thread(g, p);
read_unlock(&tasklist_lock);
+ } else {
+ printk("(elapsed %d.%d seconds) ", elapsed_csecs / 100,
+ elapsed_csecs % 100);
}

return todo ? -EBUSY : 0;