On 07/31/2015 01:16 PM, Paolo Bonzini wrote:
On 31/07/2015 19:12, Jason J. Herne wrote:
Throttle ratio is relative to CPU_THROTTLE_TIMESLICE. Take a look at how
throttle_ratio is used in the calculation:
long sleeptime_ms = (long)(throttle_ratio * CPU_THROTTLE_TIMESLICE);
A value of 1 means we sleep the same amount of time that we execute.
But that doesn't work if your timer runs every CPU_THROTTLE_TIMESLICE
milliseconds, and thus schedules async work every CPU_THROTTLE_TIMESLICE
milliseconds.
The timer would have to be scheduled every (throttle_ratio + 1) *
CPU_THROTTLE_TIMESLICE milliseconds, i.e. CPU_THROTTLE_TIMESLICE /
(1-pct) milliseconds.
Paolo
Doh! Yep :). This problem is an artifact of moving the timer_mod from
cpu_throttle_thread into cpu_throttle_timer_tick. I'll have to go back
to the review comments and look at why that was done.
--
-- Jason J. Herne (jjhe...@linux.vnet.ibm.com)
