Date: Tue, 7 Apr 2009 23:37:37 +0200 (CEST) From: Juergen Lock <nox@jelal.kn-bremen.de> To: kalinoj1@iem.pw.edu.pl Cc: freebsd-emulation@freebsd.org Subject: Re: Recent qemu and timers issue Message-ID: <200904072137.n37LbbdC071227@triton.kn-bremen.de> In-Reply-To: <200904062254.37824.kalinoj1@iem.pw.edu.pl> References: <200904032223.n33MNTiq019599@triton.kn-bremen.de>
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In article <200904062254.37824.kalinoj1@iem.pw.edu.pl> you write: >Dnia sobota 04 kwietnia 2009 o 00:23:29 Juergen Lock napisa=C5=82(a): >> In article <c948bb4de85d1b2a340ac63a7c46f6d9@iem.pw.edu.pl> you write: >> >Hi all, >> > >> >When running FreeBSD 8-CURRENT system inside a qemu machine (from the >> >latest port by nox@freebsd.org) I have strange timer problems in the >> >virtual machine. >> >> What is the host running, also current? > >Yes, the host is also running current.=20 > >But the same host has no problem with older FreeBSD kernels on the guest, e= >g.=20 >=46reeSBIe 1.1 or FreeNAS (kernel v.6.4) > OK I did some tests in the meantime on my newest box that has 4 cpus and is running 7-stable: (host) >> >> >My logs and console are full of messages like this: >> >calcru: runtime went backwards from 11248014678717988 usec to 119242 usec >> >for pid 60 (ps) >> > >> >calcru: runtime went backwards from 11248014678921829 usec to 2516605 us= >ec >> >for pid 60 (ps) >> >calcru: runtime went backwards from 7014844 usec to 6270851 usec for pid= > 0 >> >(kernel) >> > >> >It even happens for some processes to die inside qemu guest. >> >> Is this an smp host? You could try forcing qemu onto one cpu by >> doing like: >> cpuset -l 0 qemu ... >> > >Yes, it's an smp host (8 cpus). But cpuset -l 0 qemu ... (also -clock=20 >dynticks) didnt't help. > Same here with an 8.0-HEAD-20090403-JPSNAP-i386 guest. (OK I didn't see guest processes die, but I also didn't really load the guests so far...) A 7.1-RELENG_7-20090403-JPSNAP-i386 guest was not affected. >> >I tried to use all possible timers using sysctl, where I have: >> >TSC(800) HPET(900) ACPI-safe(850) i8254(0) dummy(-1000000) >> >None of these helped. >> >> On the host or in the guest? >> > >It's in the guest machine., where I tried these settings=20 > >One important thing I forgot to mention in my initial posting: >When I run 'systat -vm 1' o the guest machine - it's almost fully loaded - = >and=20 >80% (or more) of it's cpu time is spent in interrrupt handling! This is als= >o=20 >not the case with older kernels. > Hmm 'systat -vm 1' doesn't really load the 8.0 guest here. >> [snip] >> >I would greatly appreciate any help or a hint - where should I look for >> >help on this issue. >> >> If none of these help you could also try the qemu list: >> http://lists.nongnu.org/mailman/listinfo/qemu-devel >> (I think you can still post without being subscribed, altho in that case >> it may take a while for the post to get thru.) >> >> HTH, >> Juergen > >At this moment it's very hard for me to judge if it's qemu or kernel issue.. >Any thoughts? Yeah, could be one or the other. Also kinda out of ideas... Juergen
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