From: Daniel Walker <dwalker@mvista.com>
To: mingo@elte.hu
Cc: linux-kernel@vger.kernel.org
Subject: RT and pi_test
Date: Wed, 1 Jun 2005 07:13:30 -0700 (PDT) [thread overview]
Message-ID: <Pine.LNX.4.44.0506010706000.23057-100000@dhcp153.mvista.com> (raw)
I've run the pi_test a few times recently with some strange
numbers. I'm getting abnormally high task latency if I run
"./test --tasks=10 ./hist" . Depending on how long I run it, I've seen
task latency as high as 3 milliseconds, should be 0.1ms or less.
The first time I saw these latencies I has the PI abstraction applied, and
the most recent time I had the attached patch applied only. This patch is
small so I'm not sure if it could have that type of effect on task
latency.
btw, 'm not incrementing the RTC priority.
Daniel
Index: linux-2.6.11/include/linux/plist.h
===================================================================
--- linux-2.6.11.orig/include/linux/plist.h 2005-05-27 22:04:12.000000000 +0000
+++ linux-2.6.11/include/linux/plist.h 2005-06-01 13:12:37.000000000 +0000
@@ -83,7 +83,7 @@ struct plist {
* @member: the name of the list_struct within the struct.
*/
#define plist_entry(ptr, type, member) \
- container_of(plist_first(ptr), type, member)
+ container_of(ptr, type, member)
/**
* plist_for_each - iterate over the plist
* @pos1: the type * to use as a loop counter.
Index: linux-2.6.11/kernel/rt.c
===================================================================
--- linux-2.6.11.orig/kernel/rt.c 2005-06-01 13:06:21.000000000 +0000
+++ linux-2.6.11/kernel/rt.c 2005-06-01 13:50:08.000000000 +0000
@@ -773,7 +773,7 @@ static inline struct task_struct * pick_
*
* (same-prio RT tasks go FIFO)
*/
- waiter = plist_entry(&lock->wait_list, struct rt_mutex_waiter, list);
+ waiter = plist_entry(plist_first(&lock->wait_list), struct rt_mutex_waiter, list);
trace_special_pid(waiter->task->pid, waiter->task->prio, 0);
@@ -1351,7 +1351,7 @@ static void __up_mutex(struct rt_mutex *
*/
prio = mutex_getprio(old_owner);
if (!plist_empty(&old_owner->pi_waiters)) {
- w = plist_entry(&old_owner->pi_waiters, struct rt_mutex_waiter, pi_list);
+ w = plist_entry(plist_first(&old_owner->pi_waiters), struct rt_mutex_waiter, pi_list);
if (w->task->prio < prio)
prio = w->task->prio;
}
next reply other threads:[~2005-06-01 14:18 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-06-01 14:13 Daniel Walker [this message]
2005-06-05 9:36 ` RT and pi_test Ingo Molnar
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