* Dipankar Sarma <dipankar@xxxxxxxxxx> wrote: > On Mon, Feb 23, 2009 at 12:07:25PM +0100, Ingo Molnar wrote: > > > > * Vaidyanathan Srinivasan <svaidy@xxxxxxxxxxxxxxxxxx> wrote: > > > > > * Identify set of idle CPUs (CPU package) from which timers > > > can be removed > > > * Identify a semi-idle or idle CPU package to which the timers > > > can be moved > > > * Decide when to start moving timers as the system has large > > > number of idle CPUs > > > * Decide when to stop migrating as system becomes less idle > > > and utilisation increases > > > > > > Guiding all of the above decisions from user space may not be > > > fast enough. > > > > Exactly. > > That is true for power management. However there are other > situations where we may need targeted avoidance of timers. > Certain type of applications - HPC for example - prefer > avoidance of jitters due to periodic timers. It would be good > to be able to say "avoid these CPUs for timers" while they are > being used for HPC tasks. Yes - but that kind of policy should be coupled and expressed via cpusets. /proc based irq_affinity is just a limited, inflexible hack. All things IRQ partitioning should be handled via cpusets - perhaps via the 'system sets' idea from Peter? Ingo _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
