Messages in this thread | | | Date | Tue, 30 Oct 2007 11:58:08 -0700 (PDT) | From | Christoph Lameter <> | Subject | Re: [patch 08/10] SLUB: Optional fast path using cmpxchg_local |
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On Tue, 30 Oct 2007, Andrew Morton wrote:
> Let's cc linux-arch: presumably other architectures can implement cpu-local > cmpxchg and would see some benefit from doing so.
Matheiu had a whole series of cmpxchg_local patches. Ccing him too. I think he has some numbers for other architectures.
> The semantics are "atomic wrt interrutps on this cpu, not atomic wrt other > cpus", yes?
Right.
> Do you have a feel for how useful it would be for arch maintainers to implement > this? IOW, is it worth their time?
That depends on the efficiency of a cmpxchg_local vs. the interrupt enable/ disable sequence on a particular arch. On x86 this yields about 50% so it doubles the speed of the fastpath. On other architectures the cmpxchg is so slow that it is not worth it (ia64 f.e.) - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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