Hi, For now, I can only report the observed (mis) behavior of SYSV semop() call, which (on the client side) gets manifested as the following:
transport_layer_pipes::connect: lost connection to cygserver, error = 2 (this code then does a by-hand adjustment with semctl(SETVAL)). Note that there is a dedicated cygserver process running for my single-threaded application. Looking at the debugging output of cygserver, this is what I see in the log (around the only time semctl() is logged there): cygserver: /home/corinna/src/cygwin/cygwin-1.7.15/cygwin-1.7.15-1/src/cygwin-1.7.15/winsup/cygserver/transport_pipes.cc, line 132: Try to create named pipe: \\.\pipe\cygwin-13a7ed34cc1953a9-lpc cygserver: /home/corinna/src/cygwin/cygwin-1.7.15/cygwin-1.7.15-1/src/cygwin-1.7.15/winsup/cygserver/transport_pipes.cc, line 132: Try to create named pipe: \\.\pipe\cygwin-13a7ed34cc1953a9-lpc Note the double pipe creation call, and only a single "exit" log line such as: cygserver: /home/corinna/src/cygwin/cygwin-1.7.15/cygwin-1.7.15-1/src/cygwin-1.7.15/winsup/cygserver/sem.cc, line 81: leaving (3416) Cygserver does not stop (also, since SIGSYS is set to ignore in the program, it also keeps running -- although, not always quite successfully once the semop() failure occurred.) The semaphore operations are very intensive; and involve arrays of 5 sems at some times; also, there are quite large chunks of shmem updated every now and then. I studied the source of cygserver, and noticed that pipe_instance (transport_pipes.cc) is not declared "volatile". This is strange because the compiler can rearrange lines of code that include this variable, otherwise. And that seems rather critical. Right now what I observe, is that SYSV IPC is unreliable, and I'm yet to figure out why; the very same code (the locking logic) works on Linux/Solaris/Mac for years and on thousands (yes, that many) of hosts. With CYGWIN the instability can appear within a wide range of run time: from just a few minutes to some long hours, rather randomly. Any input can be greatly appreciated. Anton Lavrentiev Contractor NIH/NLM/NCBI -- 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
