-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 >>>>> It seems to be an unsettled issue, but, would any kind soul suggest >>>>> the current >>>>> best practice for setting the clock in Ubuntu Linux and Windows guests? >>>> For Linux the best source clock is the kvm pv clock (exist from 2.6.27 >>>> and above). > # qemu-system-x86_64 -clock ? > Available alarm timers, in order of precedence: > dynticks > hpet > rtc > unix > > I see no "pv clock"... > Which one should I use then? > Did I miss a ./configure or .config option? > >> No, we were talking about different clocks. >> I was explaining the guest source clock while you wanted some info for >> the host-qemu clock. Hah, gotcha. You're talking about the guest kernel as in: clocksource=[hpet|pit|tsc|acpi_pm|cyclone|scx200_hrt|kvm-clock] # cat /sys/devices/system/clocksource/clocksource0/current_clocksource kvm-clock So all good, thanks. >> You can use the default - dynticks. hpet and rtc might be good if you >> need a fine grain granularity on older < 2.6.24 host kernels. (I'm on dynticks) I guess dynticks reduces context switches on the host, but I still get hundreds per second on guests that are otherwise idle. How would I go about finding what makes them tick? Thanks Antoine > > > Cheers > Antoine > >>>> For windows, standard acpi HAL uses the rtc clock by default. As long as >>>> you use the -rtc-td-hack it won't drift. >>>> >>>> When the tsc is not stable on the host or the host cpu might get into >>>> deep sleep state (c2), you better use another source clock in the guest >>>> - for windows it should be the pmtimer (using the boot.ini). >>>> >>>>> Thanks! >>>>> >>>>> -- >>>>> 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 >>>> -- >>>> 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 -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iEYEAREKAAYFAkp2qT0ACgkQGK2zHPGK1rsSRQCfdGzkV8Gu+pTkZcnpXivXKQlt IrsAmwZAbfLzdyiWckoi80iwqc/k+0uA =Qt5o -----END PGP SIGNATURE----- -- 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
