[Skiboot] [PATCH v10 08/17] core/pci: Option for serialized jobs

Gavin Shan gwshan at linux.vnet.ibm.com
Fri May 13 10:57:00 AEST 2016

On Fri, May 13, 2016 at 10:33:27AM +1000, Stewart Smith wrote:
>Gavin Shan <gwshan at linux.vnet.ibm.com> writes:
>> Currently, the PHB reset and PCI enumeration are done concurrently
>> on multiple CPU cores. The output messages are interleaved and not
>> readable enough. This adds a option to do the jobs in serialized
>> fashion for debugging purpose only. The serialized mode should be
>> always disabled in field.
>> Signed-off-by: Gavin Shan <gwshan at linux.vnet.ibm.com>
>I think we could accomplish this in the generic code a lot neater, in
>core/cpu.c __cpu_queue_job() we could just add:
>if (cpu == NULL)
>   cpu = this_cpu();
>and then we'd be automatically able to pretty easily enable serializing
>of things that would otherwise happen in parallel.
>(better than ifdef may be something in debug descriptor... although
>setting that on boot before things start executing may be casually fun)

Good idea. Thanks, Stewart. It will be included into next revision.
The side-effect is to affect all paths including PCI enumeration. As
it's for debugging, I guess it's not a problem.

Yeah, debug descriptor should be better. I'm not sure if it has
been supported in skiboot and how it can be enabled?


>Stewart Smith
>OPAL Architect, IBM.

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