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nehalem general exploration hangs linux kernel

evermij
Beginner
80 Views
Dear Intel,

As part of a complicated software problem on a production server, we planned to use vtune as a sort of debugging tool. First we run some tests of various systems, all the system are identical.

Test system A: the first time we started the nehalem general exploration (using the command line, attaching it to the running process) the linux kernel crashed. It was impossible to ssh to the machine and on the server console we could only see 0xfff... dumps. Rebooting was the only option. Assuming it was a parameter problem, we started it again and the second time it worked fine.
Test system B: worked fine
Test system C: worked fine
Production: crashed, the same kernel crash up as stated above.

All the systems are identical (or they should be...):
Red Hat 4.1.2-46, 2x Xeon 5650 hexacore HT enabled, 12GB memory
The process is a database application running ~150 threads, but only using 100-300% cpu. The load on the test systems is less than in production.

We did not succeed in reproducing the error on our test systems, and trial/error on a production machine is unfortunatly not possible.

Could you help us out? What is going wrong?

Thanks in advance!
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4 Replies
evermij
Beginner
80 Views
using vtune_amplifier_xe_2011_update7
Vladimir_T_Intel
Moderator
80 Views
Switch off the C-states in the BIOS before running EBS analysis with VTune on a Nehalem machine.
evermij
Beginner
80 Views
Great, thanks,
Vladimir_T_Intel
Moderator
80 Views
There is a warning message displayed in GUI during EBS-based collection configuration that says to switch off C-states on Nehalem machines. I'm not sure about command line - will check it out.
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