[Ecls-list] Adding AO_REQUIRE_CAS before libatomic-ops include
dherring at tentpost.com
Fri Feb 21 23:57:46 UTC 2014
On Sat, 28 Dec 2013, Christoph Egger wrote:
> Please consider the attached patch. It enables CAS emulation on
> systems, that do not have native CAS instructions (?!), which is, for
> example, true on ARM < ARMv6
How well is the CAS emulation working for you?
If this emulation has potential bugs or may not even compile, then it
would probably be better to require a separate configuration flag.
Something like --enable-cas-emulation.
Here's a snippet from the source tree that makes me think we do not want
to set AO_REQUIRE_CAS without explicit user consent.
This emulation is slow, since it needs to disable signals. And it needs to
block in case of contention. If you care about performance on a platform
that can't directly provide compare-and-swap, there are probably better
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