[Libvirt-cim] IMPORTANT: configure Pegasus with "forceProviderProcesses=true"

[Heidi Eckhart]

Dan Smith wrote:
> HE> due to the changes made to the associations (registering the Virt_
> HE> provider for each subclass), it is now very important that Pegasus
> HE> is configured for "forceProviderProcesses=true". Otherwise only
> HE> strange things are happening ...
>
> Can you explain why you think this?  I have
> forceProviderProcesses=false and I haven't noticed any weird behavior
> thus far (aside from the libvirt init race, which is still not fully
> resolved).
>   
These are good news :).
> There's nothing about the std_association approach that should be any
> less thread-safe than the "conventional" approach, other than if
> Pegasus itself has issues with multiple calls into the broker at
> once.  If this is the case, we should be able to work around it by
> preparing additional context objects as you do when you prepare a
> thread to run, or we could provide mutual exclusion at the
> std_association layer.
>
> Before I could be convinced that we've got a thread-safety issue, I
> would want to know what behavior you're seeing, and hear from someone
> familiar with the Pegasus internals on why what we're doing is not
> safe.
>   
I was experiencing different behavior with Pegasus between setting 
forceProviderProcesses to false or true. With set to false, a provider 
request took around 5 seconds until a first output was printed out on 
stdout (CU_DEBUG) and none of the association calls have been 
successful. All request returned with "Handler not found" (CU_DEBUG), 
which was really strange, as all request have been valid ones. With 
forceProviderProcesses set to true this behavior disappeared. But after 
some more extensively testing it returned and also occurred with this 
setup :(.
So if no one else noticed such strange things, its more reasonable that 
something in my local machine setup is completely broken. I will 
investigate further into it and hopefully find some explanation for it.

Thank you for your feedback. I'm extremely happy to hear, that you 
haven't encountered similar issues.

-- 
Regards

Heidi Eckhart
Software Engineer
Linux Technology Center - Open Hypervisor

heidieck at linux.vnet.ibm.com

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