On Fri, Jan 29, 2016 at 10:53 PM, andrew cooke <[email protected]> wrote: > > i've been away from julia for a while so am not up-to-date on changes, and > am looking at an odd problem. > > i have some code, which is messier and more complex than i would like, which > is called to print a graph of values. the print code uses tasks. in 0.3 > this works, but in 0.4 the program sits, using no CPU. > > if i dump the stack (using gstack PID) i see: > > Thread 4 (Thread 0x7efe3b6bb700 (LWP 1709)): > #0 0x00007f0042e7e05f in pthread_cond_wait@@GLIBC_2.3.2 () from > /lib64/libpthread.so.0 > #1 0x00007efe3bf62b5b in blas_thread_server () from > /home/andrew/pkg/julia-0.4/usr/bin/../lib/libopenblas64_.so > #2 0x00007f0042e7a0a4 in start_thread () from /lib64/libpthread.so.0 > #3 0x00007f004231604d in clone () from /lib64/libc.so.6 > Thread 3 (Thread 0x7efe3aeba700 (LWP 1710)): > #0 0x00007f0042e7e05f in pthread_cond_wait@@GLIBC_2.3.2 () from > /lib64/libpthread.so.0 > #1 0x00007efe3bf62b5b in blas_thread_server () from > /home/andrew/pkg/julia-0.4/usr/bin/../lib/libopenblas64_.so > #2 0x00007f0042e7a0a4 in start_thread () from /lib64/libpthread.so.0 > #3 0x00007f004231604d in clone () from /lib64/libc.so.6 > Thread 2 (Thread 0x7efe3a6b9700 (LWP 1711)): > #0 0x00007f0042e7e05f in pthread_cond_wait@@GLIBC_2.3.2 () from > /lib64/libpthread.so.0 > #1 0x00007efe3bf62b5b in blas_thread_server () from > /home/andrew/pkg/julia-0.4/usr/bin/../lib/libopenblas64_.so > #2 0x00007f0042e7a0a4 in start_thread () from /lib64/libpthread.so.0 > #3 0x00007f004231604d in clone () from /lib64/libc.so.6 > Thread 1 (Thread 0x7f0044710740 (LWP 1708)): > #0 0x00007f0042e8120d in pause () from /lib64/libpthread.so.0 > #1 0x00007f0040a190fe in julia_wait_17546 () at task.jl:364 > #2 0x00007f0040a18ea1 in julia_wait_17544 () at task.jl:286 > #3 0x00007f0040a40ffc in julia_lock_18599 () at lock.jl:23 > #4 0x00007efe3ecdbeb7 in ?? () > #5 0x00007ffd3e6ad2c0 in ?? () > #6 0x0000000000000000 in ?? () > > which looks suspiciously like some kind of deadlock. > > but i am not using threads, myself. just tasks.
Tasks are not threads. You can see the threads are started by openblas. IIUC tasks can have dead lock too, depending on how you use it. > > hence the question. any pointers appreciated. > > thanks, > andrew >
