I removed the implementation of volk_malloc that uses posix_menacing by commenting everything from the #if to #else and the final #endif but the segmentation fault remains. I noticed it's being called in a few other files as well. Do I need to remove those, too? Thanks in advance. On Feb 21, 2014 10:21 AM, "Kelly Boswell" <krbosw...@gmail.com> wrote:
> Thank you, Tom. I'll try that after I'm off of work tonight. And thank you > for the great ideas, Nathan. > On Fri, Feb 21, 2014 at 2:39 AM, West, Nathan > <n...@ostatemail.okstate.edu> wrote: > > On Thu, Feb 20, 2014 at 11:25 PM, Kelly Boswell <krbosw...@gmail.com> > wrote: > >> After the make test failed for this module, I decided to poke around to > see > >> if there is an easy fix. I made a script that simply executes the test > over > >> and over until it seg faults and exits after the core file is created. > >> > >> xxxxx@xxxx:~/src/gnuradio/build/gr-digital/python/digital$ > ./runtests.sh > >> Using Volk machine: avx_64_mmx > >> Segmentation fault (core dumped) > >> > >> xxxxx@xxxx:~/src/gnuradio/build/gr-digital/python/digital$ gdb > >> /usr/bin/python2.7 core > >> (gdb) bt > >> (gdb) bt > >> #0 0x00007fe8f627fb17 in volk_32fc_32f_dot_prod_32fc_a_avx () > >> from /home/kelly/src/gnuradio/build/volk/lib/libvolk.so.0.0.0 > >> #1 0x00007fe8f52dd25f in > >> gr::filter::kernel::fir_filter_ccf::filter(std::complex<float> const*) > () > >> from > >> > /home/kelly/src/gnuradio/build/gr-filter/lib/libgnuradio-filter-3.8git.so.0.0.0 > >> #2 0x00007fe8f143c45b in > >> gr::digital::pfb_clock_sync_ccf_impl::general_work(int, std::vector<int, > >> std::allocator<int> >&, std::vector<void const*, std::allocator<void > const*> > >>>&, std::vector<void*, std::allocator<void*> >&) () > >> from > >> > /home/kelly/src/gnuradio/build/gr-digital/lib/libgnuradio-digital-3.8git.so.0.0.0 > >> #3 0x00007fe8f653809e in gr::block_executor::run_one_iteration() () > >> from > >> > /home/kelly/src/gnuradio/build/gnuradio-runtime/lib/libgnuradio-runtime-3.8git.so.0.0.0 > >> #4 0x00007fe8f6573622 in > >> gr::tpb_thread_body::tpb_thread_body(boost::shared_ptr<gr::block>, int) > () > >> from > >> > /home/kelly/src/gnuradio/build/gnuradio-runtime/lib/libgnuradio-runtime-3.8git.so.0.0.0 > >> #5 0x00007fe8f6565ea1 in > >> > boost::detail::function::void_function_obj_invoker0<gr::thread::thread_body_wrapper<gr::tpb_container>, > >> void>::invoke(boost::detail::function::function_buffer&) () > >> from > >> > /home/kelly/src/gnuradio/build/gnuradio-runtime/lib/libgnuradio-runtime-3.8git.so.0.0.0 > >> ---Type <return> to continue, or q <return> to quit--- > >> #6 0x00007fe8f6526610 in > boost::detail::thread_data<boost::function0<void> > >>>::run() () > >> from > >> > /home/kelly/src/gnuradio/build/gnuradio-runtime/lib/libgnuradio-runtime-3.8git.so.0.0.0 > >> #7 0x00007fe8f9adc94a in ?? () > >> from /usr/lib/x86_64-linux-gnu/libboost_thread.so.1.53.0 > >> #8 0x00007fe8fc8a3f6e in start_thread (arg=0x7fe8e2ffd700) > >> at pthread_create.c:311 > >> #9 0x00007fe8fc5ce9cd in clone () > >> at ../sysdeps/unix/sysv/linux/x86_64/clone.S:113 > >> > >> Of course, I had to recompile it with debugging info to glean anything > >> useful from the stack trace. So, I did that and I traced the bug to > this > >> line: > >> > >> c0Val = _mm256_mul_ps(a0Val, b0Val); > >> > >> I can't dump the values in a0Val or b0Val, though, because they're > >> intermediate values that are optimized away by the optimized kernel > code. I > >> tried stepping through the assembler instructions but I'm not familiar > with > >> the various sse and avx extensions. Heck, I'm not even familiar with the > >> x86_64 instruction set. So I have a huge learning curve ahead of me, > there. > >> Is it possible to just dump the values in these __m256 data types to a > file > >> so I can debug it that way? If that's not easy to do, then I'm willing > to > >> learn what I have to about the instruction set so I can debug this > thing. > >> But I would sure appreciate some help if anyone has some advice to > offer. > >> > >> Software version: > >> I rebased to the latest version of the next branch last night before I > went > >> to bed at around 1:30 am CDT. > >> > >> Operating System: > >> kelly@octs2:~/src/gnuradio/volk/kernels/volk$ uname -a > >> Linux octs2 3.11.0-17-generic #31-Ubuntu SMP Mon Feb 3 21:52:43 UTC 2014 > >> x86_64 x86_64 x86_64 GNU/Linux > >> It's Ubuntu 13.10 > >> > >> Hardware: ASUS X750J > >> Intel Quad Core i7 4700HQ 2.4GHz > >> > >> cpuinfo: > >> processor : 7 > >> vendor_id : GenuineIntel > >> cpu family : 6 > >> model : 60 > >> model name : Intel(R) Core(TM) i7-4700HQ CPU @ 2.40GHz > >> stepping : 3 > >> microcode : 0x8 > >> cpu MHz : 2401.000 > >> cache size : 6144 KB > >> physical id : 0 > >> siblings : 8 > >> core id : 3 > >> cpu cores : 4 > >> apicid : 7 > >> initial apicid : 7 > >> fpu : yes > >> fpu_exception : yes > >> cpuid level : 13 > >> wp : yes > >> flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca > cmov > >> pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx > pdpe1gb > >> rdtscp lm constant_tsc arch_perfmon pebs bts rep_good nopl xtopology > >> nonstop_tsc aperfmperf eagerfpu pni pclmulqdq dtes64 monitor ds_cpl vmx > est > >> tm2 ssse3 fma cx16 xtpr pdcm pcid sse4_1 sse4_2 x2apic movbe popcnt > >> tsc_deadline_timer aes xsave avx f16c rdrand lahf_lm abm ida arat epb > >> xsaveopt pln pts dtherm tpr_shadow vnmi flexpriority ept vpid fsgsbase > >> tsc_adjust bmi1 avx2 smep bmi2 erms invpcid > >> bogomips : 4789.27 > >> clflush size : 64 > >> cache_alignment : 64 > >> address sizes : 39 bits physical, 48 bits virtual > >> power management: > >> > > > > > > Hi Kelly, > > > > First, this is great debugging, thanks for getting so much info and > > trying to go for a fix on your own. > > > > On to the good stuff. I was able to reproduce this on my i7-4700MQ. > > Here's some additional info for the logs: > > > > * constellation_receiver is a hier block with a fir_filter_ccf inside > > that is calling the volk avx dot product. > > * The avx dot product proto-kernel passes VOLK QA > > * The qa_fir_filter.py is testing a fir_filter_ccf that passes its QA. > > * Just for kicks, I forced VOLK to use the generic kernel and I still > > see the segfault. > > > > A couple of things I'd like to try (and please feel free to give these a > try): > > * Go back to a commit just before fir_filter.cc started using > > volk_malloc and volk_free. (or for bonus points go back to some point > > in time when this test always passes and do a git bisect) > > * fiddle with parameters of the test, data length, number of taps in > > filter, etc. > > * Doubtful this would change, but test on different processors. It > > would be pretty wild if there was something off in the 4700 line, but > > the fact that the generic proto-kernel had the same result and nobody > > else has reported this yet is suspicious. My guess is GCC is actually > > emitting *very* similar code for the generic and avx dot product > > proto-kernels. > > > > Nathan > > > I was having similar issues this week with some AVX boxes. It looks > like it's a problem using posix_memalign (which is called by > volk_malloc if posix_memalign is available). Removing the use of > posix_memalign solves my problem. I'll work with Nathan off-list to > see about fixing this, possibly by removing the use of that version of > malloc. > > Tom >
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