On Mon, 14 Mar 2011 16:46:52 -0700 Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote: > On Mon, 14 Mar 2011 16:05:24 +0200 > Kirill A. Shutemov" <kirill@xxxxxxxxxxxxx> wrote: > > > +Overview > > +-------- > > + > > +Every task_struct has timer_slack_ns value. This value uses to > > round up +poll() and select() timeout values. This feature can be > > useful in +mobile environment where combined wakeups are desired. > > + > > +Originally, prctl() was the only way to change timer slack value of > > +a process. So you was not able change timer slack value of another > > +process. > > + > > +cgroup subsys "timer_slack" implements timer slack controller. It > > +provides a way to set minimal timer slack value for a group of > > tasks. +If a task belongs to a cgroup with minimal timer slack > > value higher than +task's value, cgroup's value will be applied. > > + > > +Timer slack controller allows to implement setting timer slack > > value of +a process based on a policy. For example, you can create > > foreground and +background cgroups and move tasks between them > > based on system state. > > (quoting myself from last time) > > Why do we need a cgroup for this as opposed to (say) inheritance over > fork(), or a system-wide knob, or a per-process/threadgroup knob, or > just leaving the existing code as-is? Presumably you felt that a > cgroup approach is better for manageability, but you didn't tell us > about this and you didn't explore alternative ways of solving the > problem-which-you-didn't-describe. > > > > > I'm still having trouble seeing why we should merge this. Who will > use it, and for what reason and what benefits will they see? > Quantified benefits, if possible! > I am planning to use it for doing resource management for a mobile device where we classify applications by groups based on priority and trust level. Then at runtime, I plan to use timer slack as one of the knobs to penalize/manage them at different degree to reduce power consumption (via reduction of #wake-ups in this case). Thanks, Jacob -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
