Messages in this thread | | | Date | Thu, 30 Sep 1999 12:11:36 +0000 | From | Manfred Spraul <> | Subject | Re: ordered memory access |
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Jes Sorensen wrote: > atomic_foo() should be ordered, at least that the idea behind it as > far as I understand.
That might be the idea, but that's not the implementation: Pentium III documentation: (24319201.pdf) > 7.2.2. Memory Ordering in the P6 Family Processors > The P6 family processors also use a processor-ordered memory > ordering model [...] > 1. Reads can be carried out speculatively and in any order.
I think there is currently no implementation for "ordered read" except rmb(): - multiple atomic_read()'s don't enforce read ordering. - there are set_?mb() function, but there are no get_?mb() functions.
I've read that rmb() is expensive on RISC architectures, what about adding "get_?mb()" functions?
-- Manfred
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