[Xen-devel] Xen's per CPU time calibration

[Xinxin Jin <xinxinjin89@xxxxxxxxx>]

Hi all,

I have a question about CPU time calibration. In timer ISR, each physical CPU read the platform time to a calibration data structure and then raise the TIME_CALIBRATE_SOFTIRQ. Later the physical CPU will do time calibration through the softirq handler local_time_calibration() based on the platform time it read before. Strictly speaking, this time is NOT the current accurate platform time already because there is a latency between read and use. So why does it work in this way? Why not directly do calibration in timer interrupt?

Thanks!

-Xinxin

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel