I''ve been working on running a SIP call server on a Xen guest domain - this requires near realtime performance, so I''ve been testing to see how Xen handles it. So far it''s been going pretty well, except I''ve noticed an odd behaviour under load. This software runs partially as a kernel object, and I''ve modified it to throw some debug messages out when it detects system timer updates (and the time since the last update was received in nanoseconds). Under light load it receives the updates every jiffy (so 4ms or 1ms depending on the HZ setting) .. under heavy load this update starts taking longer and longer, topping out at an update every 10ms. Basically my questions are, is this expected behaviour and what might cause it? I''ve tried a few things to see if it changed the results, including giving the guest domain a dedicated cpu (taken if off dom0''s list to use). I''ve also tried changing the scheduler to sedf and modified the slice and period to be small values. Other than running the guest with different jiffy periods (made no difference on the upper bound of the updates) those have been my primary attempts. Any help on this would be much appreciated. Thanks, Don _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel