Re: powerpc/opal: Wake up kopald polling thread before waiting for events

On Mon, 2016-04-07 at 04:51:44 UTC, Benjamin Herrenschmidt wrote:

On some environments (prototype machines, some simulators, etc...)
there is no functional interrupt source to signal completion, so
we rely on the fairly slow OPAL heartbeat.

In a number of cases, the calls complete very quickly or even
immediately. We've observed that it helps a lot to wakeup the OPAL
heartbeat thread before waiting for event in those cases, it will
call OPAL immediately to collect completions for anything that
finished fast enough.

Any performance/jitter impact on normal systems?

cheers