Comments on: Keeping Your VMware Linux Guest’s Clock Accurate

By: Antonio Bonifati

Antonio Bonifati — Mon, 26 Jan 2009 08:17:11 +0000

With kernel 2.6+ I experienced only time gains. I found out it is enough to only add clock=pit.

By: Carles Mateu

Carles Mateu — Thu, 16 Oct 2008 11:26:10 +0000

Power management is ACPI not APIC….

By: Admin

Admin — Thu, 18 Sep 2008 23:37:13 +0000

VMware recommends to add those kernel arguments as well in their knowledge base. Power management isn't the same in a virtual enviroment.

By: Er not quite

Er not quite — Thu, 18 Sep 2008 13:26:29 +0000

“nosmp noapic nolapic” prevents the clock from running too slowly.

Yeah and ends all power management on the PC, its not JUST for clock issues. Its for PCI issues too but you should warn people the consequences of turning off apic

By: German

German — Tue, 19 Feb 2008 14:14:35 +0000

As Erik, I was also pulling my hair out and I’m kind of bald, so you can picture the rest… hehe…
I have a Fedora Core 4 (2.6.11-1.1369_FC4smp) on a VMWare 1.0.3 and I’ve been suffering from the same problem…
I added “nosmp noapic nolapic” to the grub parameters file and now it’s working fine… I cannot believe it, this thing was driving me crazy.

Many thanks!!
German.

By: Erik

Erik — Wed, 05 Dec 2007 21:40:27 +0000

Thanks very much for sharing this. I had been pulling my hair out in solving this problem on a Ubuntu 7.10 server running VMWare 1.0.4 on an AMD64 server. All appliance clocks were off: with 2 active processors the appliance clock advanced 6 seconds in every 60 seconds (10 times slow), on 1 processor it advanced 32 seconds in a minute (twice as slow). Problems with apache log based statistics using AWstats, etc.

For me, the advice to add the kernel startup parameters “nosmp noapic nolapic” did the trick. After rebooting and an initial clock synchronization the clocks on all appliances now run more or less equal to the base server; too short a time to be certain of the effects in the long run. On 2 appliances I added ntp server to synchronize with the base server, which in turn synchronizes with time servers on the internet, to see if there is a gain in that strategy.

At least on my “server farm” all clocks are now in sync.

Thanks again,
Erik.