From: Paul H. Hargrove (PHHargrove_at_lbl_dot_gov)
Date: Mon Jan 26 2009 - 23:18:30 PST
Steven, Thanks for the bug report. I am pretty sure you have found a bug in our UPC compiler. However, there is nobody actively working on compiler bugs right now. So, if you could please go to http://upc-bugs.lbl.gov/bugzilla/ and enter your information in a bug report, that will ensure we don't loose track of it. The initial bug entry page does not allow attachments, but once the initial report has been entered, you will have the option to attach files. Thanks, -Paul Steven Vormwald wrote: > Hello, > > I've come across an odd problem that seems to only come up with > structs with 2-dimensional arrays of size 1x1. The attached code > provides an example of this. When run with N=1 (and 4 threads), the > output is unexpectedly: > 0 1 > 0 0 1 > 1 2 3 > > 0 1 > 0 0 1 > 1 2 3 > > 0 1 > 0 0 704643072 > 1 2752512 10752 > > instead of > > 0 1 > 0 0 1 > 1 2 3 > > 0 1 > 0 0 1 > 1 2 3 > > 0 1 > 0 2 3 > 1 6 11 > > Using any value of N other than 1 generates the correct output for the > number of threads. Even more odd is when I enabled the debugging > output from the code: > 0 1 > 0 0 1 > 1 2 3 > > 0 1 > 0 0 1 > 1 2 3 > > C[00].local_block[00][00] = 0 + 0 * 0 > = 0 + 0 > = 0 > C[00].local_block[00][00] = 0 + 1 * 2 > = 0 + 0 > = 0 > C[01].local_block[00][00] = 0 + 0 * 1 > = 0 + 0 > = 704643072 > C[01].local_block[00][00] = 704643072 + 1 * 3 > = 704643072 + 0 > = 704643072 > C[02].local_block[00][00] = 0 + 2 * 0 > = 0 + 0 > = 2752512 > C[02].local_block[00][00] = 2752512 + 3 * 2 > = 2752512 + 0 > = 2752512 > C[03].local_block[00][00] = 0 + 2 * 1 > = 0 + 0 > = 10752 > C[03].local_block[00][00] = 10752 + 3 * 3 > = 10752 + 0 > = 10752 > > 0 1 > 0 0 704643072 > 1 2752512 10752 > > Note that the values of A[] and B[] are printed correctly on the first > line, but the results of the multiplication and store in C[] are > incorrect. > > Changing the code to use floats or doubles instead of ints generates > similar problems. However, if the arrays are allocated dynamically > with upc_all_alloc(), the program works correctly. I tested the code > on versions 2.4 (mpi), 2.6 (smp,ibv), and 2.8 (smp,ibv) of the > Berkeley UPC compiler, all of which produce the same problem. I > haven't been able to test it on another machine, so it might be a > configuration issue, or a problem with the local C compiler (gcc (GCC) > 3.4.6 20060404 (Red Hat 3.4.6-3)). > > Attached is the source code that was used, the output of 'upcc > -version' for each of the versions of the compiler used, as well as > the output run on 4 threads with N=1,2. I fixed the order of the > output lines so they lined up properly, but otherwise did not change > the output. > > Steven Vormwald -- Paul H. Hargrove PHHargrove_at_lbl_dot_gov Future Technologies Group Tel: +1-510-495-2352 HPC Research Department Fax: +1-510-486-6900 Lawrence Berkeley National Laboratory