Am Tue, 18 Jun 2013 19:12:06 -0700 schrieb Sean Kelly <s...@invisibleduck.org>:
> On Jun 18, 2013, at 7:01 AM, Marco Leise <marco.le...@gmx.de> wrote: > > > Am Mon, 17 Jun 2013 10:46:19 -0700 > > schrieb Sean Kelly <s...@invisibleduck.org>: > > > >> On Jun 13, 2013, at 2:22 AM, Marco Leise <marco.le...@gmx.de> wrote: > >> > >>> Here is an excerpt from a stack trace I got while profiling > >>> with OProfile: > >>> > >>> #0 sem_wait () from /lib64/libpthread.so.0 > >>> #1 thread_suspendAll () at core/thread.d:2471 > >>> #2 gc.gcx.Gcx.fullcollect() (this=...) at gc/gcx.d:2427 > >>> #3 gc.gcx.Gcx.bigAlloc() (this=..., size=16401, poolPtr=0x7fc3d4bfe3c8, > >>> alloc_size=0x7fc3d4bfe418) at gc/gcx.d:2099 > >>> #4 gc.gcx.GC.mallocNoSync (alloc_size=0x7fc3d4bfe418, bits=10, > >>> size=16401, this=...) gc/gcx.d:503 > >>> #5 gc.gcx.GC.malloc() (this=..., size=16401, bits=10, > >>> alloc_size=0x7fc3d4bfe418) gc/gcx.d:421 > >>> #6 gc.gc.gc_qalloc (ba=10, sz=<optimized out>) gc/gc.d:203 > >>> #7 gc_qalloc (sz=<optimized out>, ba=10) gc/gc.d:198 > >>> #8 _d_newarrayT (ti=..., length=4096) rt/lifetime.d:807 > >>> #9 sequencer.algorithm.gzip.HuffmanTree.__T6__ctorTG32hZ.__ctor() > >>> (this=..., bitLengths=...) sequencer/algorithm/gzip.d:444 > >>> > >>> Two more threads are alive, but waiting on a condition > >>> variable (i.e.: in pthread_cond_wait(), but from my own and > >>> not from druntime code. Is there some obvious way I could have > >>> dead-locked the GC ? Or is there a bug ? > >> > >> I assume you're running on Linux, which uses signals (SIGUSR1, > >> specifically) to suspend threads for a collection. So I imagine what's > >> happening is that your thread is trying to suspend all the other threads > >> so it can collect, and those threads are ignoring the signal for some > >> reason. I would expect pthread_cond_wait to be interrupted if a signal > >> arrives though. Have you overridden the signal handler for SIGUSR1? > > > > No, I have not overridden the signal handler. I'm aware of the > > fact that signals make pthread_cond_wait() return early and > > put them in a while loop as one would expect, that is all. > > Hrm... Can you trap this in a debugger and post the stack traces of all > threads? That stack above is a thread waiting for others to say they're > suspended so it can collect. I could do that (with a little work setting the scenario up again), but it wont help. As I said, the other two threads were paused in pthread_cond_wait() in my own code. There was nothing special about their stack trace. -- Marco
