On Mon, Mar 7, 2016 at 10:18 PM, West, Nathan <n...@ostatemail.okstate.edu> wrote:
> On Mon, Mar 7, 2016 at 2:32 PM, devin kelly <dwwke...@gmail.com> wrote: > >> Hello, >> >> I've built a flowgraph (grc, python attached) that usually (but not >> always) produces a segfaults in volk_32fc_x2_multiply_32fc_a_avx2_fma. The >> segfault occurs in the FFT filter in correlation estimator block. I'm not >> sure if it's the Volk code that's causing the segfault or the GR code >> calling it or what I'm putting into GR. I've got a back trace below if >> that helps. >> >> Also, at the tag gate in my flowgraph I would usually have a USRP >> transmitter and a USRP receiver in a before the Correlation Estimate in a >> separate flowgraph but since I can re-create the segfault in the flowgraph >> I simplified. >> >> I'm using GR 3.7.9, Volk 1.2.1 and UHD 3.9.2 (though I don't call any UHD >> code here). >> >> Thanks for any help, >> Devin >> >> $ gdb /usr/bin/python core.13408 >> GNU gdb (GDB) Red Hat Enterprise Linux 7.6.1-80.el7 >> Copyright (C) 2013 Free Software Foundation, Inc. >> License GPLv3+: GNU GPL version 3 or later < >> http://gnu.org/licenses/gpl.html> >> This is free software: you are free to change and redistribute it. >> There is NO WARRANTY, to the extent permitted by law. Type "show copying" >> and "show warranty" for details. >> This GDB was configured as "x86_64-redhat-linux-gnu". >> For bug reporting instructions, please see: >> <http://www.gnu.org/software/gdb/bugs/>... >> Reading symbols from /usr/bin/python2.7...Reading symbols from >> /usr/bin/python2.7...(no debugging symbols found)...done. >> (no debugging symbols found)...done. >> >> [Thread debugging using libthread_db enabled] >> Using host libthread_db library "/lib64/libthread_db.so.1". >> Core was generated by `python2 ./segfault_test.py'. >> Program terminated with signal 11, Segmentation fault. >> #0 0x00007f11a4d064c0 in volk_32fc_x2_multiply_32fc_a_avx2_fma () from >> /local_disk/gr_3.7.9/lib/libvolk.so.1.2.1 >> Missing separate debuginfos, use: debuginfo-install >> python-2.7.5-34.el7.x86_64 >> (gdb) bt >> #0 0x00007f11a4d064c0 in volk_32fc_x2_multiply_32fc_a_avx2_fma () at >> /local_disk/gr_3.7.9/lib/libvolk.so.1.2.1 >> #1 0x00007f119c1d0006 in gr::filter::kernel::fft_filter_ccc::filter(int, >> std::complex<float> const*, std::complex<float>*) () >> at /local_disk/gr_3.7.9/lib64/libgnuradio-filter-3.7.9.so.0.0.0 >> #2 0x00007f119c4d724f in gr::digital::corr_est_cc_impl::work(int, >> std::vector<void const*, std::allocator<void const*> >&, std::vector<void*, >> std::allocator<void*> >&) () at >> /local_disk/gr_3.7.9/lib64/libgnuradio-digital-3.7.9.so.0.0.0 >> #3 0x00007f11a52b1f57 in gr::sync_block::general_work(int, >> std::vector<int, std::allocator<int> >&, std::vector<void const*, >> std::allocator<void const*> >&, std::vector<void*, std::allocator<void*> >> >&) () at /local_disk/gr_3.7.9/lib64/libgnuradio-runtime-3.7.9.so.0.0.0 >> #4 0x00007f11a527a6bd in gr::block_executor::run_one_iteration() () at >> /local_disk/gr_3.7.9/lib64/libgnuradio-runtime-3.7.9.so.0.0.0 >> #5 0x00007f11a52baf60 in >> gr::tpb_thread_body::tpb_thread_body(boost::shared_ptr<gr::block>, int) () >> at /local_disk/gr_3.7.9/lib64/libgnuradio-runtime-3.7.9.so.0.0.0 >> #6 0x00007f11a52aebc1 in >> boost::detail::function::void_function_obj_invoker0<gr::thread::thread_body_wrapper<gr::tpb_container>, >> void>::invoke(boost::detail::function::function_buffer&) () at >> /local_disk/gr_3.7.9/lib64/libgnuradio-runtime-3.7.9.so.0.0.0 >> #7 0x00007f11a5260910 in >> boost::detail::thread_data<boost::function0<void> >::run() () >> at /local_disk/gr_3.7.9/lib64/libgnuradio-runtime-3.7.9.so.0.0.0 >> #8 0x00007f11a40b824a in thread_proxy () at >> /lib64/libboost_thread-mt.so.1.53.0 >> #9 0x00007f11bfa38dc5 in start_thread () at /lib64/libpthread.so.0 >> #10 0x00007f11bf05d28d in clone () at /lib64/libc.so.6 >> >> >> _______________________________________________ >> Discuss-gnuradio mailing list >> Discuss-gnuradio@gnu.org >> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio >> >> > I couldn't reproduce this on my machine with avx2. Your GRC flowgraph > didn't draw anything, so I replaced your FG with random source(0,255) -> > const. modulator -> correlation est -> sinks. > > I'm wondering if a bad vector length is getting passed in by accident. Can > you get the parameters to the VOLK call when it crashes? If you're not > familiar with gdb do something like the following: > gdb> f 0 > gdb> info variables > Also, I'd like to know what processor you have. I don't think it has anything to do with this bug, but my processor (i7-4700MQ) doesn't generally see much benefit from AVX much less AVX2. What were the times volk_profile gives you for this kernel? (use volk_profile -R 32fc_x2_multiply)
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