On Thu, Feb 10, 2011 at 02:22:21PM -0800, jacob pan wrote: > On Thu, 10 Feb 2011 11:11:17 -0800 > Matt Helsley <matthltc@xxxxxxxxxx> wrote: > > > On Wed, Feb 09, 2011 at 07:06:15PM -0800, Arjan van de Ven wrote: > > > On 2/9/2011 7:04 PM, Matt Helsley wrote: > > > >On Tue, Feb 08, 2011 at 05:05:41PM -0800, > > > >jacob.jun.pan@xxxxxxxxxxxxxxx wrote: > > > >>From: Jacob Pan<jacob.jun.pan@xxxxxxxxxxxxxxx> > > > >> > > > >>Freezer subsystem is used to manage batch jobs which can start > > > >>stop at the same time. However, sometime it is desirable to let > > > >>the kernel manage the freezer state automatically with a given > > > >>duty ratio. > > > >>For example, if we want to reduce the time that backgroup apps > > > >>are allowed to run we can put them into a freezer subsystem and > > > >>set the kernel to turn them THAWED/FROZEN at given duty ratio. > > > >> > > > >>This patch introduces two file nodes under cgroup > > > >>freezer.duty_ratio_pct and freezer.period_sec > > > >> > > > >>Usage example: set period to be 5 seconds and frozen duty ratio > > > >>90% [root@localhost aoa]# echo 90> freezer.duty_ratio_pct > > > >>[root@localhost aoa]# echo 5000> freezer.period_ms > > > >I kept wondering how this was useful when we've got the "cpu" > > > >subsystem because for some reason "duty cycle" made me think this > > > >was a scheduling policy knob. In fact, I'm pretty sure it is -- it > > > >just happens to sometimes reduce power consumption. > > > > > > > >Have you tried using the cpu cgroup subsystem's share to see if it > > > >can have a similar effect? > > > > > > does the cpu cgroup system work on a 20 to 30 second time window? > > > > I don't think so -- it works directly with the scheduler IIRC. > > > I played with cpu subsystem a little today, it is for real-time tasks > only. By data type of cpu.rt_period_us cpu.rt_runtime_us, it > actually has a pretty long time window (35 mins, int type at usec > resolution). > For some reason, I could not even get cpu subsystem to work with RT > task to work on 38-rc2 kernel. Here is what I did > - mount and create cpu cgroup fs > - launch task with SCHED_RR > - attach task to my newly created cgroup > - adjust cpu.rt_period_us cpu.rt_runtime_us > But it never changed percentage of runtime. The ask in the cpu cgroup > always run at 100% or more than the runtime_us as I specified. I have > tried both with system idle and background tasks. > > I do agree that dealing with group scheduler directly might be more > natural. but the hurdle might be changing cpu subsystem to support > non-rt, and deal with scheduler heuristics. Even though it probably requires more effort that seems like the right approach. Cheers, -Matt Helsley _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/containers
