On Tue, Sep 15, 2015 at 12:04 AM, Oliver Yang <yang_oliver@xxxxxxxxxxx> wrote: > Hi Guys, > > I found below patch for KVM TSC trapping / migration support, > > https://lkml.org/lkml/2011/1/6/90 > > It seemed the patch were not merged in Linux mainline. > > So I have 3 questions here, > > 1. Can KVM support TSC trapping today? If not, what is the plan? Not without a patch. Did you want to trap RDTSC? RDTSC works without trapping thanks to hardware support. > > 2. What is the solution if my SMP Linux guest OS doesn't have reliable > TSC? If you are seeing an unreliable TSC in your guest, maybe your host hardware does not support a synchronized TSC across CPUs. I can't recall how to check for this. There might be a flag in your host's /proc/cpuinfo. > > Because the no TSC trapping support, will kvmclock driver handle all > TSC sync issues? > > 3. What if my Linux guest doesn't have kvmclock driver? The guest will use a different clock source (e.g. acpi-pm). Note the RDTSC[P] instruction will still work just fine. > > Does that mean I shouldn't run TSC sensitive application in my guest > OS? > > BTW, my application is written with lots of rdtsc instructions, and > which performs well in VMware guest. Does it not work well in KVM? -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
