Since some people crunching and folding here are running or thinking about running Linux, I thought I would share a way for stress testing a system for overclock stability without having to load Windows with P95/LinX first. This should help reduce the setup time when you plan to roll out a new farm of Linux crunchers. For stress testing, we will use Linpack from Intel. Linpack is actually the program that LinX and IBT in Windows wraps around. This document assumes the user has basic knowledge of Linux including downloading a file, opening a terminal, running basic commands, and creating a file with an editor. As always with overclocking and stress testing, there is some risk of hardware damage especially when overvolting, overheating, or pushing the hardware too much in general. Linpack is known for significantly stressing the hardware so take care when running this program.
The first step is to grab the latest linpack for Linux. http://software.intel.com/en-us/articles/intel-math-kernel-library-linpack-download/
Next, extract the library and change directory to the appropriate location where the linpack program is.
tar xf l_lpk_p_10.3.7.011.tgz
Now we will create an input file for linpack. Think of this as the same thing as the options you select in LinX except you will specify these options in a text file. Use the editor of your choice like vi or nano. Here is an example input file:
Sample Intel(R) Optimized LINPACK Benchmark data file (lininput_xeon64)
Intel(R) Optimized LINPACK Benchmark data
1 # number of tests
23346 # problem sizes
23346 # leading dimensions
1 # times to run a test
4 # alignment values (in KBytes)
The relevant parts include problem size and times to run a test. The problem size can match what you normally run in LinX. The above example will use most memory on a 6GB system. Be careful not to strain your IMC too much by setting to large of a problem size especially if overclocking the IMC, having all memory slots populated, or excessive VTT. Overclocking and stress testing is not worth killing your IMC over! Be careful! You can specify how many times to run the test via line 6. Optionally you can run multiple problems in a row and increase the number in line number 3 to correspond to the number of problems you plan to run and add the additional problem sizes on line 4 and 5. Refer to the sample file called lininput_xeon64 in the same directory for more information.
Now you will want to open a second terminal to monitor core temps while running LinX. You can use lm_sensors for that. The command is called sensors. You will need the processor core temp modules loaded like coretemp. Use sensors-detect to find those. You can then fire up linpack from the first terminal using the following commands:
By default linpack only runs on the number of physical cores and does not take into account hyperthreading. In the case of a 920 or 2600K, by default linpack would 4-threads instead of 8. The second export command manually sets the number of threads for linpack to run to 8. If you have an AMD processor or Intel with HT disabled or do not care for stress testing with HT then ignore the export lines.
Run sensors as many times as necessary from the second terminal to make sure your processor does not overheat. You can open a third terminal and run top to see memory and processor usage. Depending on your distribution, there may other handy tools you can use to monitor your system.
Here is a screenshot of one pass I ran via my Linux system. Keep in mind that 20 passes of linpack does not guarantee that BOINC or folding will run stable 24/365 but it should be a good start. Good luck!