segfault running BENCHMARK1 on Mac OS X with xlf

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amaxwell
Posts: 6
Joined: Tue Dec 14, 2004 11:37 pm
Location: PNNL, Sequim WA

segfault running BENCHMARK1 on Mac OS X with xlf

#1 Unread post by amaxwell »

I've successfully run the BENCHMARK1 test case on a Linux cluster (Rocks 3.3.0) with the Absoft compiler and MPI, but I'm getting a segfault when I try to run this case on my OS X system (1.8G5 DP, either serial or with OpenMP, IBM xlf 8.1). I've run the damee_4 and upwelling examples successfully on the Mac, so this should be possible.

Stepping through with gdb, the crash appears to occur at CALL lmd_vmix_tile (lmd_vmix.f90, line 70 or so). I'm more familiar with C, so any suggestions on how to debug this would be helpful! This is after time step 0 is written to stdout, BTW.

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kate
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Joined: Wed Jul 02, 2003 5:29 pm
Location: CFOS/UAF, USA

#2 Unread post by kate »

I'm more familiar with xlf on IBM. However, you could be running into memory troubles. Are you linking with -bmaxdata:0x70000000? The default is 256 MB which isn't big enough for BENCHMARK1. How much memory do you have, anyway?

amaxwell
Posts: 6
Joined: Tue Dec 14, 2004 11:37 pm
Location: PNNL, Sequim WA

#3 Unread post by amaxwell »

kate wrote:I'm more familiar with xlf on IBM. However, you could be running into memory troubles. Are you linking with -bmaxdata:0x70000000? The default is 256 MB which isn't big enough for BENCHMARK1. How much memory do you have, anyway?
I'm not specifying that in the link options, so I'll give it a shot and post the results here. I have 1 GB of RAM, and the ppc/xlf/OpenMP smoked the x86/Absoft/MPI combinations that I've tried; I'm curious to see how it compares with the benchmarks that Rich Signell posted here.

amaxwell
Posts: 6
Joined: Tue Dec 14, 2004 11:37 pm
Location: PNNL, Sequim WA

#4 Unread post by amaxwell »

Well, I feel dumb; I'm hitting the stack limit, and the answer was here:
viewtopic.php?t=149

Increasing the number of tiles works for now. Interestingly, -bmaxdata doesn't appear in the xlf user's guide, so perhaps it's specific to the IBM machines?

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