Re: Lahey Fortran and Core 2 duo

mecej4 wrote:
Harvey Gratt wrote:
Tim Prince wrote:
Harvey Gratt wrote:
Interesting issue. I have access to two Dell Precision M4300 workstation laptops. On both machines I installed my copy of Lahey Fortran Pro 5.5 (LF9555). I also have an old Dell Dimension D8300 desktop with the compiler on it.

Even though the laptops are suppose to much, much quicker from all aspects (cpu, HDD, bus, memory, etc), a 6 dof simulation runs over 3 times slower on the "faster" laptops.

Are there any known issues with Lahey Fortran and Core 2 Duo (Santa Rosa) machines?

You don't give much specific to go on, so I resort to web searches for data.
I wouldn't call the typical 1.8Ghz CPU of the M4300 faster than the typical 3.2Ghz CPU of D8300, even with the typical 30% higher instruction per clock rate of SSE code, which you may not have selected (is your compiler too old for SSE?). As you didn't say anything about threading, or OpenMP, I'll guess you're leaving 1 core idle. It's a known issue that a single thread uses only 1 core.
Even if the laptop uses DDR2-667 and the desktop DDR2-533, it doesn't necessarily make any difference with only 1 thread running. There probably aren't any commercial Fortran compilers yet which optimize for the Core 2 rather than the older CPUs, not that we know enough about your code to say it would make a difference.
I don't have any data about the disks to go on, except that I've never seen a laptop disk compete on speed.


Some additional info. The M4300 laptop was a replacement for an older IBM Thinkpad R40 (1.4GHZ cpu, 512M ram, 5400 rpm HDD). The old R40 ran the simulation in the same time as the desktop - almost 3 times faster than the M4300 (2.00GHZ cpu, 2GB ram, 7200 rpm HDD). Since these slow speeds appear on 2 different M4300's, I don't think it's a hardware issue.

You may receive useful suggestions if you are able/willing to provide some more information:

Is your program CPU bound, memory bound or I/O bound? Does it do many network transactions? Does the M4300 run other applications as fast as one would expect? Are you running the same OS, and are the configurations similar? What is the typical run-time that instigated your complaint (i.e., < 1 s, or < 1 min, or ~ some hours)?

Have you run a utility such as CPU-Z on both computers?

-- mecej4

Thanks,
Harvey

1. Program runs out of a dos full screen window. Probably cpu bound. Heavy on floating point operations.


2. No network transactions.

3. Win XP Pro on all machines. Similar configurations (software).

4. Run time is about 8 seconds vs. 24 seconds. Minimal I/O output.

5. In general, the M4300's are as fast as would be expected with other applications.

6. Have not run any utilities to measure speed.

Thanks,
Harvey
.

Relevant Pages

  • Re: Lahey Fortran and Core 2 duo
    ... Even though the laptops are suppose to much, much quicker from all aspects, a 6 dof simulation runs over 3 times slower on the "faster" laptops. ... Are there any known issues with Lahey Fortran and Core 2 Duo machines? ... I wouldn't call the typical 1.8Ghz CPU of the M4300 faster than the typical 3.2Ghz CPU of D8300, even with the typical 30% higher instruction per clock rate of SSE code, which you may not have selected. ...
    (comp.lang.fortran)
  • Re: Lahey Fortran and Core 2 duo
    ... Even though the laptops are suppose to much, much quicker from all aspects, a 6 dof simulation runs over 3 times slower on the "faster" laptops. ... Are there any known issues with Lahey Fortran and Core 2 Duo machines? ... I wouldn't call the typical 1.8Ghz CPU of the M4300 faster than the typical 3.2Ghz CPU of D8300, even with the typical 30% higher instruction per clock rate of SSE code, which you may not have selected. ...
    (comp.lang.fortran)
  • Re: Lahey Fortran and Core 2 duo
    ... Even though the laptops are suppose to much, much quicker from all aspects, a 6 dof simulation runs over 3 times slower on the "faster" laptops. ... Are there any known issues with Lahey Fortran and Core 2 Duo machines? ... I wouldn't call the typical 1.8Ghz CPU of the M4300 faster than the typical 3.2Ghz CPU of D8300, even with the typical 30% higher instruction per clock rate of SSE code, which you may not have selected. ... As you didn't say anything about threading, or OpenMP, I'll guess you're leaving 1 core idle. ...
    (comp.lang.fortran)
  • Re: Lahey Fortran and Core 2 duo
    ... Even though the laptops are suppose to much, much quicker from all aspects, a 6 dof simulation runs over 3 times slower on the "faster" laptops. ... Are there any known issues with Lahey Fortran and Core 2 Duo machines? ... I wouldn't call the typical 1.8Ghz CPU of the M4300 faster than the typical 3.2Ghz CPU of D8300, even with the typical 30% higher instruction per clock rate of SSE code, which you may not have selected. ... As you didn't say anything about threading, or OpenMP, I'll guess you're leaving 1 core idle. ...
    (comp.lang.fortran)
  • Lahey Fortran and Core 2 duo
    ... I have access to two Dell Precision M4300 workstation laptops. ... Are there any known issues with Lahey Fortran and Core 2 Duo machines? ...
    (comp.lang.fortran)