On 12/01/2010 10:43 AM, Avi Kivity wrote:
On 12/01/2010 06:33 PM, Anthony Liguori wrote:
BTW, by this logic, even a 1-byte dirty bitmap is only 16mb which can
be read in less than 16ms so where is the reported 24 minute stall
coming from?
a) we read the bitmap more than once
Not in a single iteration which is what the "stall" would consist of.
b) the 1ms is based on "we read" it with longs and optimized, just now
we have to read it by byte and inside the byte.
Byte accesses verse long access doesn't turn 16ms into 24 minutes.
We need actual measurements instead of speculations.
Yes, I agree 100%. I think the place to start is what I suggested in a
previous note in this thread, we need to measure actual stall time in
the guest.
Regards,
Anthony Liguori
