Messages in this thread | | | Date | Thu, 27 Jan 2005 16:53:30 -0800 | From | Paul Jackson <> | Subject | Re: [patch, 2.6.10-rc2] sched: fix ->nr_uninterruptible handling bugs |
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A long time ago, Linus wrote: > An atomic op is pretty much as expensive as a spinlock/unlock pair on x86. > Not _quite_, but it's pretty close.
Are both read and modify atomic ops relatively expensive on some CPUs, or is it just modify atomic ops?
(Ignoring for this question the possibility that a mix of read and modify ops could heat up a cache line on multiprocessor systems, and focusing for the moment just on the CPU internals ...)
-- I won't rest till it's the best ... Programmer, Linux Scalability Paul Jackson <pj@sgi.com> 1.650.933.1373, 1.925.600.0401 - 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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