Comments on: Quickpost: RTC problems in Debian on Dell PowerEdge servers

By: VMWare RTC Meldungen » flocki wills wissen

VMWare RTC Meldungen » flocki wills wissen — Fri, 12 Sep 2008 14:04:33 +0000

[...] http://nixy.dk/2007/10/24/quickpost-rtc-problems-in-debian-on-dell-poweredge-servers/ [...]

By: Ben

Ben — Thu, 03 Jul 2008 13:43:02 +0000

I’ve been having timing issues with vmplayer on a custom kernel. I have done EVERY possible thing I could think of when building a custom kernel for vmplayer but the time always runs really fast and the reported CPU is much slower than it actually is. I read all of vmware’s documentation and all I found is that the kernel requires the rtc and parallel port support. Using the tsc as the system timer works fine for the guest (with the exception of choppy audio) but performance suffers. I would like to be able to use the hpet. Could you possibly post your entire kernel config? btw, vmware’s documentation for linux is disgusting so I appreciate posts like this.
Thanks,
Ben

By: Rada

Rada — Sat, 26 Apr 2008 12:12:22 +0000

That is very odd. I’ve never – at all – come across this issue with 64-bit architectures.

Did you try poking in your kernel config?

By: brandon

brandon — Thu, 17 Apr 2008 01:11:04 +0000

revisiting this issue… apparently this isn’t the magic bullet…

/proc$ zcat config.gz |grep CONFIG_RTC
CONFIG_RTC=y
/proc$ zcat config.gz |grep HPET
CONFIG_HPET_EMULATE_RTC=y
/proc$ dmesg | tail -2
rtc: lost some interrupts at 512Hz.
rtc: lost some interrupts at 512Hz.

Hardware is SC1435.
Linux hostname 2.6.22-3-amd64 #1 SMP Mon Nov 12 17:53:18 UTC 2007 x86_64 GNU/Linux

Any other ideas?

By: Rada

Rada — Sun, 09 Mar 2008 13:43:28 +0000

th3D:
Well, in my situation (With a Dell PowerEdge server), the BIOS didn’t have an option to turn off HPET. Also, why NOT use HPET?

By: th3D

th3D — Sun, 09 Mar 2008 04:31:25 +0000

WHY rebuild kernel when HPET usually can be turned off in BIOS? HPET isnt a requirement but rather a supplement, im sure HPET will be supported in the next major Debian release, until then Debian is still one of the best distros and i hope people dont start recompiling or change distro without taking 30 seconds to look for it in Bios first.

By: Rada

Rada — Mon, 07 Jan 2008 07:00:54 +0000

The important part is setting “RCT” to be built-in. Have you made sure of that?

By: brandon

brandon — Mon, 07 Jan 2008 06:58:48 +0000

Apparently Debian has CONFIG_HPET_EMULATE_RTC=y set by default now (At least in 2.6.22-3-amd64 it is). Hardware is Dell PE 1435.

But I’m still getting the infamous “rtc: lost some interrupts at 512Hz.”

By: Dean

Dean — Sun, 06 Jan 2008 09:34:44 +0000

Thank you for this post. It was a major time saver and much appreciated.

By: Rada

Rada — Mon, 29 Oct 2007 20:03:50 +0000

Hi Ralf,
This does not only apply to Dell hardware. If anybody is experiencing these specific problems with RTC on their hardware, I think this might work.

I’ve read up a bit on HPET, and it seems Dell is one of the few companies who were the first to manufacture hardware with it.

Also, any Linux OS that displays the symptoms is affected. =)