From mboxrd@z Thu Jan 1 00:00:00 1970 From: a.p.zijlstra@chello.nl (Peter Zijlstra) Date: Tue, 11 Oct 2011 11:13:19 +0200 Subject: sched: ARM: arch_scale_freq_power In-Reply-To: References: <1318319852.14400.65.camel@laptop> Message-ID: <1318324399.14400.71.camel@laptop> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Tue, 2011-10-11 at 10:51 +0200, Vincent Guittot wrote: > I have several goals. The 1st one is that I need to put more load on > some cpus when I have packages with different cpu frequency. That should be rather easy. > I also study if I can follow the real cpu frequency but it seems to be > not so easy. Why not? > I have noticed that the cpu_power is updated periodical > except when we have a lot of newly_idle events. We can certainly fix that. > Then, I have some use cases which have several running tasks but a low > cpu load. In this case, the small tasks are spread on several cpu by > the load_balance whereas they could be easily handled by one cpu > without significant performance modification. That shouldn't be done using cpu_power, we have sched_smt_power_savings and sched_mc_power_savings for stuff like that. Although I would really like to kill all those different sched_*_power_savings knobs and reduce it to one. > If the cpu_power is > higher than 1024, the cpu is no more seen out of capacity by the > load_balance as soon as a short process is running and teh main result > is that the small tasks will stay on the same cpu. This configuration > is mainly usefull for ARM dual core system when we want to power gate > one cpu. I use cyclictest to simulate such use case. Yeah, but that's wrong.