On 2018 Feb 26 (Mon) at 18:52:34 -0800 (-0800), Pratik Vyas wrote:
:* Dave Voutila <d...@sisu.io> [2018-02-22 23:40:21 -0500]:
:
:> > Synopsis: VMD consumes 100% cpu after unpausing guest
:> > Category: amd64
:> > Environment:
:> System : OpenBSD 6.2
:> Details : OpenBSD 6.2-current (GENERIC.MP) #10: Wed Feb 21 21:26:27
MST 2018
:>
dera...@amd64.openbsd.org:/usr/src/sys/arch/amd64/compile/GENERIC.MP
:>
:> Architecture: OpenBSD.amd64
:> Machine : amd64
:>
:> > Description:
:>
:> Not sure if this is a known issue, but I couldn't find anything
:> searching the lists.
:>
:> Using an Alpine Linux guest vm, I can successfully pause the guest using
:> `vmctl pause 1` and some time later resume it using `vmctl unpause 1`.
:>
:> Unpausing works as the guest comes back to life, I can SSH back in, and
:> it's fine. However, on the host the vmd process representing that guest
:> sits at 100% CPU utilization with 1 thread constantly queueing onto a
:> cpu and running. The guest reports normal load so it must be one of the
:> 2 threads.
:
:This should fix it.
:
:Use rtc_reschedule_per in mc146818_start instead of re arming the
:periodic interrupt without checking if it's enabled in REGB.
:
:ok?
:
:--
:Pratik
:
:Index: usr.sbin/vmd/mc146818.c
:===================================================================
:RCS file: /home/pdvyas/cvs/src/usr.sbin/vmd/mc146818.c,v
:retrieving revision 1.15
:diff -u -p -a -u -r1.15 mc146818.c
:--- usr.sbin/vmd/mc146818.c 9 Jul 2017 00:51:40 -0000 1.15
:+++ usr.sbin/vmd/mc146818.c 27 Feb 2018 02:47:18 -0000
:@@ -354,6 +354,6 @@ mc146818_stop()
:void
:mc146818_start()
:{
:- evtimer_add(&rtc.per, &rtc.per_tv);
: evtimer_add(&rtc.sec, &rtc.sec_tv);
:+ rtc_reschedule_per();
:}
:
This helps a lot with the CPU load on a vmd host. Drops my single guest
from ~50% CPU to ~9% CPU on the host.
OK
(btw, should rtc_fireper() receive a similar change?)
--
The right half of the brain controls the left half of the body. This
means that only left handed people are in their right mind.
