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I am currently running Ubuntu 14.04 LTS (fresh install) on a Dell Precision 7910. When I attempt to do any heavy analysis (ie. processing 4-10 large files at one time), the machine completely freezes. Neither the mouse nor keyboard respond, and I end up doing a hard reboot. ALT + PrtScn + R E I S U B did not do anything.

I looked at the log files, but there is nothing there from the time of the freeze.

Although I am quickly able to reproduce this problem running a particular java program called GATK, I have also run into it while running C programs. Sometimes it freezes right away, and other times it takes 20-30 minutes.

The Dell ePSA diagnostics test and memtest86+ test both passed.

Can anyone provide a step-by-step way to figure out what may be causing the system to freeze?

Thanks for your help! RC

  • FYI, I also attempted to SSH into my machine to determine if this was a video problem, but was unable to. I seems like an entire system freeze. – user442099 Aug 21 '15 at 23:22
  • Which system log files were you checking, and do the programs that you are attempting to run, write their own logs? – Kevin Aug 22 '15 at 15:10
  • I would first check video driver. Please add output of lspci -k | grep -EA2 'VGA|3D to your question. – Pilot6 Aug 22 '15 at 16:12
  • @ Kevin: The log files in /var/log/ did not show anything. And the program I am using does write a log file, but nothing was recorded there. Everything was just ended abruptly. – user442099 Aug 24 '15 at 19:41
  • @Pilot6: Here is the output of video driver: 04:00.0 VGA compatible controller: NVIDIA Corporation GF119 [NVS 310] (rev a1) Subsystem: NVIDIA Corporation Device 094e Kernel driver in use: nouveau – user442099 Aug 24 '15 at 19:45
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I would start further investigating by monitoring system resources leading up to the freeze. Basic tools like htop or top, and iotop work well. Maybe RAM or swap is filling up, or disk I/O is being held by 1 process?

You can try setting the CPU affinity of your intensive process, or setting its niceness (I believe there is I/O niceness as well), to try to prevent resource starvation for kernel/system processes.

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After hours of googling, I read something similar where a complete system freeze was caused by some sort of error in the processor clock (?). I went into the BIOS and disabled the "Intel Hyperthreading Technology", and this seems to have fixed it. Although my machine now shows 8 cores, rather than 16 cores, it is no longer crashing. I can live with this, however, if anyone has any ideas on how to enable the hyperthreading without major crashes, I would love to try it.

Thanks, RC

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  • Your problem is in a wrong video driver. – Pilot6 Aug 24 '15 at 19:50
  • @Pilot6: I am unfamiliar with the details of video drivers. Can you suggest a change I could make that would make the system more stable? --Thanks, RC – user442099 Aug 24 '15 at 19:55
  • That's what I am trying to do. Please read carefully my last comment to your question and do what I asked there. Then I will give you a solution. – Pilot6 Aug 24 '15 at 19:57

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