K. Noel Belcourt wrote:
I should have mentioned that I ran ipcs, here's the output.
[~]$ ipcs -a
------ Shared Memory Segments -------- key shmid owner perms bytes nattch status 0x00000000 0 root 777 94208 0 0x00000000 65537 root 777 94208 1
------ Semaphore Arrays -------- key semid owner perms nsems
------ Message Queues -------- key msqid owner perms used-bytes messages
What kind of IPC object does this test create? Why is there no IPC object in the kernel data structures? I don't believe there's anything running on my system that would call ipcrm.
This depends on the system, but for the moment it creates a shared memory with an anonymous mutex. Interprocess uses POSIX primitives (see /dev/shm or /dev/sem for POSIX resources) instead of system V ones and emulates them with memory mapped files in the temp directory if POSIX shared memory is not provided (unistd.h does not define POSIX_SHARED_MEMORY_OBJECTS > 0). Your stack points that the thread is blocked on: while(value == InitializingSegment || value == UninitializedSegment){ detail::thread_yield(); value = detail::atomic_read32(patomic_word); } which means that the thread has found the shared memory created but the flag to synchronize the thread opening the segment until the segment is initialized by the thread that created the segment is not updated. This could mean that the thread that created the segment has been killed before initializing properly the segment.
There's two copies of this test currently running on my system (gcc-3.4.3 and gcc-4.0.1), would that matter?
19303 kbelco 25 0 14944 1380 1188 R 98.9 0.0 40:00.53 named_recursive 19328 kbelco 25 0 14988 1360 1176 R 98.9 0.0 34:25.73 named_recursive
This is really nasty. You should only have one instance, since the test is just single-threaded. This can be causing several problems. Can you investigate a bit why is this happening? I'm thinking about the use of shared memory + anonymous synchronization objects to emulate named synchronization objects and I think I should use native named semaphores when available in systems that provide them. I think it will use less resources. Added to my to-do list. Regards, Ion