Messages in this thread | | | Subject | Re: [PATCH -tip-rcu] Make rcutorture more vicious: make quiescent rcutorture less power-hungry | From | Darren Hart <> | Date | Mon, 23 Jun 2008 17:54:09 +0000 |
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On Sun, 2008-06-22 at 13:17 -0700, Arjan van de Ven wrote: > On Sun, 22 Jun 2008 13:06:38 -0700 > "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> wrote: > > > This patch makes the non-module rcutorture a bit more friendly to > > the power-conservation code. This is a rather simple-minded approach. > > More sophisticated approaches would get rid of the rcutorture tasks > > while rcutorture execution was suppressed, but attempts thus far to > > do this have not gone well -- calling rcu_torture_init() from a /proc > > callout results in oopses. > > > > Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> > > --- > > > > rcutorture.c | 5 ++++- > > 1 file changed, 4 insertions(+), 1 deletion(-) > > > > diff -urpNa -X dontdiff > > linux-2.6.26-rc4-rcut2-proc/kernel/rcutorture.c > > linux-2.6.26-rc4-rcut3-procq/kernel/rcutorture.c --- > > linux-2.6.26-rc4-rcut2-proc/kernel/rcutorture.c 2008-06-22 > > 10:29:04.000000000 -0700 +++ > > linux-2.6.26-rc4-rcut3-procq/kernel/rcutorture.c 2008-06-22 > > 12:20:10.000000000 -0700 @@ -196,7 +196,10 @@ static void > > rcu_stutter_wait(void) { while (stutter_pause_test > > || !rcutorture_runnable) > > - schedule_timeout_interruptible(1); > > + if (rcutorture_runnable) > > + schedule_timeout_interruptible(1); > > + else > > + schedule_timeout_interruptible(HZ); > > } > > could you also make it use round_jiffies_relative() to make the power > impact even less..... > (by coalescing various "once a second" timers like this)
I'm a little concerned about how this will affect real-time performance, as queueing up lots of timers all at once can lead to long running timer expiration handlers. If just a schedule_timeout, I suppose we are only looking at a process wakeup, as opposed to a softirq context callback function?
Thanks,
-- Darren Hart Real-Time Linux Team Lead IBM Linux Technology Center
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