Re: PHP performance on Xen domU with mulitple vcpu

[Emmanuel Dreyfus <manu%netbsd.org@localhost>]

On Sat, Apr 05, 2025 at 04:02:28PM -0700, Greg A. Woods wrote:
> > Indeed, this is 4.3.1
> I'm not sure I understand that number.

Sorry, I am not sure how I managed to write that. I meant 4.18.3
xen_version            : 4.18.3_20240909nb1

> That's what I meant -- that with clockinterrupt then ntpd is able to
> keep the system wallclock time in sync vs. falling out of sync when
> using xen_system_time.

Yes, this is what happens.

> One other question I forgot to ask:  With xen_system_time does
> timekeeping work OK for the first few days and then go bad, or is it bad
> right from boot? 

ntpq -c kerninfo shows maximum error steadily rising from 16000 by 0.5 
each second.  That starts at boot time, and it never syncs.
# while true; do ntpq -c kerninfo|grep "maximum error"; sleep 1; done
maximum error:         16326.5
maximum error:         16327
maximum error:         16327.5
maximum error:         16328
maximum error:         16328.5
maximum error:         16329



-- 
Emmanuel Dreyfus
manu%netbsd.org@localhost