[Wien] Help with Operation System

[M. Koshino]

Dear Prof. Peter Blaha,

Thank you for your advice.

> Thanks for the benchmark times. This seems to be a nice processor.
> Unfortunately, some of them are not very clear.
> 
> a) Please set:
> export OMP_NUM_THREADS=1 (2 and 4)
> run    x lapw1
> and check the timings (it should go faster when using more threads). You can also
> verify using the "top" command whether the lapw1 command uses 1,2 or 4 cores.

The result of running "x lapw1" after changing the number of threads is as follows:

export OMP_NUM_THREADS=1
test_case.output1:       TIME HAMILT (CPU)  =     6.8, HNS =     4.5, HORB =     0.0, DIAG =    26.2
test_case.output1:       TIME HAMILT (WALL) =     6.9, HNS =     4.5, HORB =     0.0, DIAG =    26.4
("top" command shows cpu % = 99)

export OMP_NUM_THREADS=2
test_case.output1:       TIME HAMILT (CPU)  =    10.6, HNS =     5.7, HORB =     0.0, DIAG =    32.1
test_case.output1:       TIME HAMILT (WALL) =     7.1, HNS =     2.9, HORB =     0.0, DIAG =    16.3
("top" command shows cpu % = 199)

export OMP_NUM_THREADS=4
test_case.output1:       TIME HAMILT (CPU)  =    20.1, HNS =     8.4, HORB =     0.0, DIAG =    48.9
test_case.output1:       TIME HAMILT (WALL) =     7.2, HNS =     2.1, HORB =     0.0, DIAG =    12.7
("top" command shows cpu % = 398)


> 
> b) x lapw1 -p    is not enough. What you should do is:
>     create 4 identical directories, then open 4 windows, change into these 4 directories and
>     run  "x lapw1" at the same time 2 or 4 times and check the timings.

Running two x lapw1 on two different windows gives the results as follows:

#1
test_case.output1:       TIME HAMILT (CPU)  =     7.0, HNS =     4.7, HORB =     0.0, DIAG =    31.3
test_case.output1:       TIME HAMILT (WALL) =     7.1, HNS =     4.7, HORB =     0.0, DIAG =    31.5
#2
test_case.output1:       TIME HAMILT (CPU)  =     7.0, HNS =     4.7, HORB =     0.0, DIAG =    31.1
test_case.output1:       TIME HAMILT (WALL) =     7.1, HNS =     4.7, HORB =     0.0, DIAG =    31.3


Running four x lapw1 on four different windows gives the results as follows:

#1
test_case.output1:       TIME HAMILT (CPU)  =     7.5, HNS =     5.3, HORB =     0.0, DIAG =    48.4
test_case.output1:       TIME HAMILT (WALL) =     7.7, HNS =     5.4, HORB =     0.0, DIAG =    48.8
#2
test_case.output1:       TIME HAMILT (CPU)  =     7.6, HNS =     5.2, HORB =     0.0, DIAG =    48.4
test_case.output1:       TIME HAMILT (WALL) =     7.8, HNS =     5.3, HORB =     0.0, DIAG =    48.8
#3
test_case.output1:       TIME HAMILT (CPU)  =     7.6, HNS =     5.2, HORB =     0.0, DIAG =    47.9
test_case.output1:       TIME HAMILT (WALL) =     7.8, HNS =     5.3, HORB =     0.0, DIAG =    48.3
#4
test_case.output1:       TIME HAMILT (CPU)  =     7.8, HNS =     5.2, HORB =     0.0, DIAG =    48.0
test_case.output1:       TIME HAMILT (WALL) =     8.0, HNS =     5.3, HORB =     0.0, DIAG =    48.4


> 
> c) Most likely, the mpi-benchmark is not using mpi,.... But forget this test.
> 

OK, I will skip this.

Thank you again for the comment.

FYI, I got a personal email from a person watching this mailing list but who was reluctant to write in English.

Another option of OS for core i7 2600 could be RedHat Enterprise Linux 6.

CentOS 6 can be another option which will be released next week.

Scientific Linux 6 which is equivalent to CentOS is already released.

Kind regards,

Masanori Koshino

Nanotube Research Center

AIST, JAPAN
m-koshino at aist.go.jp