Date: Wed, 21 Dec 2011 17:48:52 +0400 From: Maxim Dounin <mdounin@mdounin.ru> To: Ivan Voras <ivoras@freebsd.org> Cc: freebsd-stable@freebsd.org Subject: Re: Unbalanced timer interrupts under VMWare? Message-ID: <20111221134852.GT67687@mdounin.ru> In-Reply-To: <jcsebc$d7n$1@dough.gmane.org> References: <jcsebc$d7n$1@dough.gmane.org>
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Hello! On Wed, Dec 21, 2011 at 12:02:04PM +0100, Ivan Voras wrote: > I have a strange situation on a VMWare 5-hosted machine: > > # vmstat -i > interrupt total rate > irq1: atkbd0 74 0 > irq6: fdc0 11 0 > irq15: ata1 17 0 > irq18: em0 42122 1 > cpu0:timer 2246291 54 > irq256: mpt0 141402 3 > cpu1:timer 280800 6 > Total 2710717 65 > > The cpu0 timer interrupt rate is 54 Hz and cpu1 rate is 6 Hz. The > same is visible when monitoring the system in real time with "systat > -vm". > > This is a default FreeBSD 9 RC3 amd64 system, HZ is the default 100. > Unless the tickless kernel project has advanced more than I think, It is, actually. Many thanks to mav@ for his amazing work. $ sysctl kern.eventtimer.periodic kern.eventtimer.periodic: 0 $ vmstat -i | grep timer cpu0:timer 72769640 47 And down to 37 i/s as seen in "systat -vm". Idle virtual machine now takes 2 times less CPU on my laptop as seen from the host. > this looks like a problem... so I looked elsewhere and it turns out > I cannot get more than about 55 interrupts/s with the disk > controller either. Happily goes to 6k i/s here (though it's under VirtualBox and a bit old -current, not 9.0). (Just in case: note that vmstat report rate since boot, "systat -vm" may be better to look at current values.) > Any ideas? I have another host running VMware 5 but only an 8-stable > machine in it, which works fine. Does anyone else run 9.x on VMware > 5? > > The host is a Xeon X3360 CPU (4 cores, no HTT, 2.8 GHz). Maxim Dounin
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