[syslinux] Domain-specific HLT when idle

H. Peter Anvin hpa at zytor.com
Sat May 2 18:13:37 PDT 2009


Peter Iannucci wrote:
> Hello hpa,
> 
> We are developing a Xen-based virtualization service, and we are trying
> to reduce excessive CPU utilization at isolinux boot prompts.  When
> users boot up a virtual machine on an isolinux boot CD, the CPU starts
> spinning at 100%.  These machines frequently get left in this state for
> days or weeks, degrading the service for everyone else.
> 
> You replied to the work-around discussed in the earlier thread at
> 
> http://syslinux.zytor.com/archives/2005-June/005291.html
> 
>> Breaks serial console.
>>     -hpa
> 
> In our case, the serial console is not an issue.  We would like to
> submit a patch to isolinux which HLTs on getchar if isolinux is not
> running with the serial console option.  Do you think this is the right
> solution to this problem?  Can we work with you to resolve this?
> 

It would *probably* be okay to do when serial console is not enabled,
but it seems a bit crude... and also it's somewhat confusing that one
should enable serial console and get drastically different behavior.

What is much more confusing to me is why do you have VMs left like this
for "days or weeks"?

	-hpa

-- 
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.




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