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| Date: | Sat, 02 Jun 2012 00:07:50 +0200 |
| From: | Otto Meta <otto DOT meta AT sister-shadow DOT de> |
| Reply-To: | cygwin AT cygwin DOT com |
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| To: | nemesis AT icequake DOT net |
| CC: | cygwin AT cygwin DOT com |
| Subject: | sem_wait frequently returning with EINTR [Was: Re: How to "bisect" Cygwin?] |
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> The basic issue is that sem_wait() is being kicked out with EINTR > extremely frequently (9 out of 10 times or more), which slows my code > to a crawl as it repeatedly retries sem_wait() until it finally > returns zero. In 1.7.9, it does not appear that sem_wait() is > preempted in this fashion; the thread would simply wait on the > semaphore until it was sem_post()'d and then continue as expected. Are you using signals or functions that use signals internally? Signals are a bit wonky in 1.7.9 and they seem to be pretty much broken in 1.7.12 and newer (I didn’t try any snapshots). Have a look at the problem I reported: http://cygwin.com/ml/cygwin/2012-05/msg00186.html While the cancelling part seems to be mostly fixed by now, the signal part is still unchanged. Maybe you could try test 3 from my test program attached to the above mentioned post. If its output changes along with your program’s behaviour when you try different Cygwin versions, your problem could be signal-related. Warren Young wrote in http://cygwin.com/ml/cygwin/2012-06/msg00032.html: > You should just get an infinite series of "Child timed out normally waiting > for the semaphore." messages from it after initialization, one per second. This works for me out of the box, but if I create one or more pthreads before the alarm loop it just fails: Some other thread gets woken up and the main thread stays stuck in sem_wait. If Ryan had told us more about his program, we’d know whether he uses multiple threads or multiple processes... Cheers, Otto -- Problem reports: http://cygwin.com/problems.html FAQ: http://cygwin.com/faq/ Documentation: http://cygwin.com/docs.html Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple
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