Re: Semi up to date JOBS list

From: Juan J. Quintela (quintela@fi.udc.es)
Date: Fri Jun 16 2000 - 06:58:26 EST


>>>>> "manfred" == Manfred Spraul <manfred@colorfullife.com> writes:

Hi

manfred> Is that bit often set, or usually zero?
manfred> If the bit is usually zero, we might replace TestAndClear with
manfred> TestAndTestAndClear: we avoid the lock cycle if the bit was already 0.
manfred> Atomic operations are extremely slow, e.g. the ia64 spinlock asm code
manfred> internally uses TestAndTestAndSet in spin_lock();

Could you elaborate please? I see no reference to TestAndTestAndSet
in the code. The bit is supposed to be normally 0, but it depends of
your workload. How do you write that function/macro????

TIA, Juan.

-- 
In theory, practice and theory are the same, but in practice they 
are different -- Larry McVoy

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