Dan Halbert wrote:
We have been seeing failures with CentOS 4.4 i386 (not x86_64) running
compute-intensive programs on Tyan K8SRE (S2891) Tymotherboards,
running Opteron 265's. This motherboard is used in the Tyan barebones
box GT24 (B2881). We have these boards populated with 8GB of RAM,
consisting of mixed 2GB and 1GB sticks.
The symptom is that CPU-bound programs (may or may not be related to
floating point) fail randomly and intermittently, with wrong answers
or segfaults. Running several in parallel seems to make the failures
more likely. We have not seen any kernel crashes. It is not hard to
reproduce the problem with some internal programs we have; it takes
only a few minutes.
as a FPU test, try this... from a user account...
mkdir mprime
cd mprime
wget ftp://mersenne.org/gimps/mprime2414.tar.gz
tar xzvf mprime2414.tar.gz
./mprime -A0 -t &
./mprime -A1 -t &
(if you have two dual core opterons, do this twice more with -A2 and -A3)
this will HAMMER the cpu/cache/memory bus with intensive FPU
operations. let it run all night on an otherwise idle box, note any
errors spewed to the terminal. each instance will use about 16MB of
ram, and will be executing near peak speed FPU/SSE operations. it
auto-nice's itself to minimize the impact on the rest of the system.
your CPUs will run hotter than they've ever run before :)
hey, I thought mixing dimm sizes was verbotten on opterons?
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