[ANNOUNCE] libxshmfence 1.0
Mouse
mouse at Rodents-Montreal.ORG
Sat Nov 2 17:13:51 CET 2013
> Here's the detailed write up I did that describes the SyncFence
> semantics and how those map directly to Linux Futexes: [...]
This makes SyncFences sound like condition variables under another
name, to me. Surely pthreads has condition variables? (I don't know
pthreads....)
However, I'd give a very close to look to the synchronization code.
SyncFences look like condition variables _without_ the associated
mutexes. The mutex is there for very good reason, though, leading me
to suspect that SyncFence-using code is full of race conditions.
(Suspect. Since I haven't read it, I'm not sure; there probably exist
uses for mutex-free condvars, and this may be one of them....)
In any case, the mutex does not have to actually cause any trouble, if
present; it can be acquired and released immediately around the condvar
calls.
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