Re: rtc: lost some interrupts at 256Hz

[Michael Monnerie <michael.monnerie@it-management.at>]

On Freitag, 21. April 2006 00:22 Lee Revell wrote:
> I asked about the app because I was wondering whether he had a server
> or a desktop.

It's all servers. The Hz rate can change over time:

Mar  3 02:04:41 baum kernel: rtc: lost some interrupts at 256Hz.
Mar  3 02:04:53 baum kernel: rtc: lost some interrupts at 256Hz.
Mar  3 02:04:55 baum kernel: rtc: lost some interrupts at 256Hz.
Mar  3 02:38:19 baum kernel: rtc: lost some interrupts at 256Hz.
Mar  3 02:42:22 baum kernel: rtc: lost some interrupts at 256Hz.
Mar 16 15:53:50 baum kernel: rtc: lost some interrupts at 2048Hz.
Mar 16 15:54:01 baum kernel: rtc: lost some interrupts at 2048Hz.
Mar 16 16:29:33 baum kernel: rtc: lost some interrupts at 2048Hz.
Mar 29 23:01:36 baum kernel: warning: many lost ticks.

Interesting may be the fact that VMware runs on at least some hosts. I 
didn't check if all servers have it, but I found a good article on 
vmware support:

http://www.vmware.com/support/kb/enduser/std_adp.php?p_sid=tthOqz5i&p_lva=&p_faqid=1420&p_created=1093994398&p_sp=cF9zcmNoPTEmcF9ncmlkc29ydD0mcF9yb3dfY250PTE3JnBfc2VhcmNoX3RleHQ9bG9zdCBzb21lIGludGVycnJ1cHRzJnBfc2VhcmNoX3R5cGU9NyZwX3Byb2RfbHZsMT1_YW55fiZwX3Byb2RfbHZsMj1_YW55fiZwX3NvcnRfYnk9ZGZsdCZwX3BhZ2U9MQ**&p_li=

So as a summary:
- Lee Revell said changing preemption model from server to voluntary or 
preemption could help
- increasing HZ on the vm-host, decreasing in the vm-clients should 
help, according to VMware support

It would be good if this information is spread on the support lists, I 
saw that question a lot. Also, a short text under Documentation in the 
kernel source could be nice, explaining why this happens and what to do 
then.

I will try the suggestion from the vmware support link I posted above, 
and will report back.

mfg zmi
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