On Thursday 06 March 2008 16:43:18 Yang, Sheng wrote: > On Thursday 06 March 2008 16:06:51 Avi Kivity wrote: > > Yang, Sheng wrote: > > > Here is the updated patch. I kept 0xff because I think it's OK for > > > understand easily. :) > > > > Any news on the regression with older Linux guests? That's the only > > thing keeping my from applying the patchset. > > Not much. PIT interrupts injection is all right, 1000 per second. Just > found two clock source in guest got problem: PM timer and TSC. Seems both > due to compensate for lost ticks. Get rid of something like "jiffies_64 += > lost -1" get the time ok. > > And I think it's a exist bug. As you see, in most condition, userspace pit > + in kernel irqchip resulted in time flow slowly, due to the lost of > interrupts. But RHEL4 runs even faster than host... > > I will do more investigate.
Get some clues. It seems like for the kernel which is active to inject lost interrupt, when some PIT interrupts were pending, the TSC/other clocksource got the wrong impression that some PIT interrupt lost, then using itself's counter to adjust the jiffies. So the problem occurs. Xen adjust TSC to fit this mode. It pull TSC backward to get the correct value when injecting one PIT interrupt. But this would causing trouble on some Windows. Then, it got the "time mode" concept... -- Thanks Yang, Sheng ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ kvm-devel mailing list kvm-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/kvm-devel
