Re: [RFC PATCH v2] membarrier: expedited private command

From: Paul E. McKenney
Date: Tue Aug 01 2017 - 09:24:59 EST


On Tue, Aug 01, 2017 at 12:22:03PM +0200, Peter Zijlstra wrote:

[ . . . ]

> As to scheduler IPIs, those are limited to the CPUs the user is limited
> to and are rate limited by the wakeup-latency of the tasks. After all,
> all the time a task is runnable but not running, wakeups are no-ops.

Can't that wakeup-latency limitation be overcome by a normal user simply
by having lots of tasks to wake up, which then go back to sleep almost
immediately? Coupled with very a low-priority CPU-bound task on each CPU?

Thanx, Paul