Messages in this thread | | | Date | Wed, 16 Jul 2008 23:49:32 +0100 | From | Ben Hutchings <> | Subject | Re: [PATCH] cputopology: Always define CPU topology information [4th try] |
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Nathan Lynch wrote: > Hi Ben- > > Ben Hutchings wrote: > > Not all architectures and configurations define CPU topology information. > > This can result in an empty topology directory in sysfs, and requires > > in-kernel users to protect all uses with #ifdef - see > > <http://marc.info/?l=linux-netdev&m=120639033904472&w=2>. > > > > The documentation of CPU topology specifies what the defaults should be > > if only partial information is available from the hardware. So we can > > provide these defaults as a fallback. > > I've been looking at adding topology information to powerpc and I came > across this. > > I understand the need for fallback definitions of the topology APIs > within the kernel, but I'm not sure I agree with exposing these things > in sysfs unconditionally -- the default values for physical_package_id > and core_id don't really make sense on powerpc (and other non-x86 > architectures, I suspect).
In what way are they wrong?
> Would you object to a patch which exposes in sysfs only the topology > information which the architecture provides?
I was primarily concerned with having the fallbacks available in-kernel. However, I don't think you will be doing user-space any favours by requiring checks for missing attributes for ever.
Ben.
-- Ben Hutchings, Senior Software Engineer, Solarflare Communications Not speaking for my employer; that's the marketing department's job.
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