Basic Intel Linpack Benchmark Questions

Basic Intel Linpack Benchmark Questions

Hello everyone,

my name is Florian and i have some basic questions for you about the Linpack Benchmark App. It has become a part of my responsibility at work to certify Workstation system for the Energy Star. About a week ago i received my first WS system and have to use the Linpack Suite to test it.

I originally come from Network Eng. and got moved to my new department, so please excuse my beginner questions and my english since this is not my native language.

If i understood correctly the Linpack App uses the Intel optimized librarys for the architecture to be tested. In my case its a 64bit dual xeon platform with 8GB of main memory. I have downloaded and installed the Linpack benchmark suite and executed it. It is running on a 64bit MS Windows OS. It is asking for several inputs

*leading dimensions of array

*trials to run

*number of equations to solve

*data alignment value

Could you please explain to me how to calculate these values and what they mean?

I am sorry to bother you with this most likely basic question but i would apreciate any help given.

Best regards

Florian

6 posts / 0 new
Last post
For more complete information about compiler optimizations, see our Optimization Notice.

Florian,

There is quite a bit of good information in the benchmarkslinpack directory. Sounds like linpack_xeon64.exe is the right benchmark for you. You can run "linpack_xeon64.exe -e" to get a length discussion of parameters and what combinations are best. But maybe easier would be to start by just trying the example input file: "linpack_xeon64.exe < lininput_xeon64". The -e option help also discusses what each line of this input file does.

To address your question briefly:

  • leading dimension is the stride between columns of the matrix
  • trials to run is the number of times to run the problem (e.g., you might want more stability and run a problem multiple times, or you might want to run multiple sizes)
  • number of equations is the size of the matrix
  • data alignment value is the way the memory is aligned. From the extended help
    • The alignment value allows the arrays to be aligned to the value specified, zero means that no specific alignment will be performed - the arrays are used as they are allocated. The best performance is likely to be obtained when arrays are aligned to the page size boundary.

Todd

Thank you for the tips,

i have reviewed the programm a bit more. I am still wondering tough, how is the problem size determinded? I found a formula which states that the number of bytes (from main memory) should be divided by 8 and then by a 1000. The the root should be calculated based on that which is "n". What is the Matrix?

Kind regards

Florian

The Linpack benchmark performs an LUfactorization then solve of a matrix. So

Number of equations = size of matrix = problem size = "n"

Todd

Hello,

I am Aesha, I want to do some analysis based on parameters present in o/p file of linpack_xeon64.exe .

Plz tell me meaning of following parameters:

1. Residual

2. Residual(norm)

3.Check

Hi Aesha,

Residual and residual norm indicate the accuracy of the solution. Residual vector is: r = b - A*x, where A is the coefficient matrix, x is the solution vector and b is rhs vector. The reported residual number is the absolute maximum value in the r vector. residual (norm) is similar, however this time the residual is scaled by the machine epsilon, norm of the matrix A and number of equations. The "Check" indicates that residual and residual (norm) is within acceptable error limits.

Thank you.

 

 

Leave a Comment

Please sign in to add a comment. Not a member? Join today