On Aug 7 10:12, Corinna Vinschen wrote: > On Aug 7 05:02, Lavrentiev, Anton (NIH/NLM/NCBI) [C] via cygwin wrote: > > I'm noticing that in a high-contention situation (many processes try > > to get ahold of a semaphore) semget() on Cygwin starts to return > > EAGAIN (try again) after about 62 processes has gotten to call > > semget() and are actively competing for the semaphore (i.e. using the > > semaphore ID semget() returned to them). > > > > EAGAIN is not documented in any of semget() API documentation that I > > can find. > > > > I understand that in Cygwin semget() is implemented as a connection to > > cygserver, and the error probably stems from there, but I don't think > > that such a code is appropriate as a final errno. And why is there a > > limit, to begin with? What exactly imposes it? > > The number of parallel open pipes, for instance. By default, 10 > worker threads handle the load and up to 62 processes can be handled > in parallel. If the numbers are too low in your scenario, try to > raise them in /etc/cygserver.conf.
Apart from that, the preferred way to use semaphores is to use POSIX semaphores, that is, sem_open and friends. These don't require cygserver. Corinna -- Corinna Vinschen Cygwin Maintainer
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