Messages in this thread | | | Date | Fri, 16 Jun 2006 16:19:20 -0500 (CDT) | From | Chase Venters <> | Subject | Re: FOR REVIEW: New x86-64 vsyscall vgetcpu() |
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(Sorry for the empty reply! Pine over a laggy SSH connection is annoying sometimes)
On Fri, 16 Jun 2006, Andi Kleen wrote:
> >> To this last point, it might be more reasonable to map in a page that >> contained a new structure with a stable ABI, which mirrored some of >> the task_struct information, and likely other useful information as >> needs are identified in the future. In any case, it would be hard >> to beat a single memory read for performance. > > That would mean making the context switch and possibly other > things slower.
Well, if every process had a page of its own, what would the context switch overhead be?
But, I'm not advocating exporting anything. Though I sort of like the vgetcpu() idea because I was working on a user-space slab allocator recently and magazines could use vgetcpu() instead of pthread keys. (Also means if threads > cpus I'd get better results).
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