Messages in this thread | | | Date | Thu, 6 Aug 2009 12:42:40 +0200 | From | Andreas Herrmann <> | Subject | Re: [PATCH 0/5 v4] x86: Adapt CPU topology detection for AMD Magny-Cours |
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On Wed, Aug 05, 2009 at 10:23:54PM +0200, Brice Goglin wrote: > Andreas Herrmann wrote: > > Changes to previous patch set: > > - fixed allnoconfig compile error and link error if CONFIG_PCI=n > > - fixed hotplug issue: cpumask of siblings sharing same L3 were not > > properly updated > > - properly allocate cpu_node_map > > > > Current patch set contains 5 patches: > > - patch 1 adapts common code to show cpu_node_id, > > cpu_node_siblings and cpu_node_siblings_list in > > /sys/devices/system/cpu/cpu*/topology > > - patch 2 prepares arch/x86 to provide cpu_node information > > - patch 3 sets up cpu_node information for AMD Magny-Cours CPU > > - patch 4 fixes L3 cache information for Magny-Cours > > - patch 5 fixes mcheck code for Magny-Cours > > > > Hello Andreas, > > Reading your first submission I find something disturbing. You say that > we'll have the following sibling information: > > Level | Set of CPUs > --------------|--------------- > phys_package | core_siblings > cpu_node | cpu_node_siblings > core | thread_siblings > thread | one CPU
> This breaks the existing convention/semantics.
Isn't the existing convention that core_siblings denotes all CPUs on same socket.
> Currently core/thread_siblings contains the cpumask covering *all* > siblings of current core/thread object. What you're adding only > shows the cpumask of current "cpu_node" object in > cpu_node_siblings. I don't have any preference between both > semantics, but I think "cpu_node" should use the semantics that > "core" and "thread" do. So the above should be changed into:
> Level | Set of CPUs > --------------|--------------- > phys_package | cpu_node_siblings > cpu_node | core_siblings > core | thread_siblings > thread | one CPU
Of course I thought also to implement it this way because it looks more consistent, but IMHO the patches are less intrusive if this scheme is _not_ used. Instead I kept core_siblings as is ("for historic reasons", nobody needs to accustom to new semantics). And use cpu_node_siblings where it really matters.
But this reminds me that some documentation is required to describe the new attributes.
What do others think?
Thanks, Andreas
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