linux-kernel - Question: RT schedular : task_tick_rt(struct rq *rq, struct task_struct *p) : decreases overhead when rq->nr

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <000501c7d945$f30af1a0$6501a8c0@earthlink.net>
Date:	Tue, 7 Aug 2007 15:54:41 -0700
From:	"Mitchell Erblich" <erblichs@...thlink.net>
To:	"Ingo Molnar" <mingo@...e.hu>
Cc:	"Linux Kernel Mailing List" <linux-kernel@...r.kernel.org>
Subject: Question: RT schedular : task_tick_rt(struct rq *rq, struct task_struct *p) : decreases overhead when  rq->nr_running == 1

Ingo Molnar and group,

If their is a single RT task on this rq, then why not just reset the
timeslice and return??? Just MAYBE decreasing re-scheduling
overhead..

Thus,,,,

After
    p->time_slice = static_prio_timeslice(p->static_prio);

Why isn't their a check like
    if  (rq->nr_running == 1)
         return;

Which world remove the need for any recheduling
or requeue'ing...

Mitchell Erblich
FYI: below is believed to be a snap of the current/ orig func
-----------------------------


+static void task_tick_rt(struct rq *rq, struct task_struct *p)
+{
+ /*
+  * RR tasks need a special form of timeslice management.
+  * FIFO tasks have no timeslices.
+  */
+ if (p->policy != SCHED_RR)
+  return;
+
+ if (--p->time_slice)
+  return;
+
+ p->time_slice = static_prio_timeslice(p->static_prio);
+ set_tsk_need_resched(p);
+
+ /* put it at the end of the queue: */
+ requeue_task_rt(rq, p);
+}
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/