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?
