Console applications slow down XP systems

[Martien_J]

I recently migrated two projects from FPS 4 to IVF8.1. These two projects are of the console type. In FPS4 the associated executables created a problem on WinXP systems. They slowed down operation very much and especially file opendialogs inMS Office did take a very long time (so I am not sure whether the problem was due to lack of processor speed or lack of resources). Anyway, the solution for me at that time was to lower the priority of the process by including the following statements.

Integer*4 hProcess,dwPriority

Logical CheckPriority

hProcess= GetCurrentProcess() dwPriority = 64 ! idle priority CheckPriority = SetPriorityClass(hProcess, dwPriority)

After migrating to IVF8.1, I thought I could eliminate this part and go back to a normal priority for the calculation process. However, when I build my projects without these statementsI findexactly the same problem I had before with the compiled code of FPS4. So the solution is simply to leave the codeaboveinside my program but I am still wondering why this is necessary and also wondering whether it now takes longer than necessary to complete my calculations ?

Thanks,

Martien

[Steven_L_Intel1]

If you have a compute-bound process, it is going to slow down the rest of the system. There is nothing inherent in the compiler that changes this. Set the priority low if you want the program to run "in the background".

Of course, an Intel processor with Hyper-Threading Technology or one of the new dual-core processors will help with this too.

[Martien_J]

Thanks Steve for your reply. I understand that any computational intensive application will slow down the system and I appreciate your suggestion for more powerfull processors. However, in my caseI don't thinkthis explains it all.

If I don't set the priority level the process will get a "normal" priority, following the Windowstask manager. I can still do many things at a reasonable speed. Even launching a second instance of my own application. One of the things which gives problem is when I open an MS Office application (Excel or Word) and use the menu's file - open. The open dialog appears and it can take minutes before the files appear in this dialog. Also simply opening the Windows explorer can lead to a long delaybefore the screen fills. My application is notreally "disk oriented" and reads/writes only a few reasonably small files, so I am quit wondering what causes this behaviour. As mentioned, setting the priority for my application to low, the problem disappears completely.

I agree with you, this may have nothing to do with the compiler itself. There was however a historical reasonfor my question. When I run in the pastFPS4 onWin95/Win98 systems, I had no problems.When the application was migrated to WinXP (still withFPS4) the problem started. I didblaim at that time theFPS4 compiler, but may havebeen wrong.

Thanks,

Martien

PS the MsOffice version was MSoffice97 on all systems mentioned above.

[TimP]

My guess would be that ifort 8.1 is hogging more memory (RAM). XP also hogs RAM and disk, at least when kept up to date. XP SP2 could have difficulty running on 256MB, where 64MB would be plenty for Win95. On my P4, with 2GB RAM installed, large applications built with ifort 8.1 run significantly better under Windows 2000 than under recent XP. There is about 200MB more virtual memory available to an application built with ifort under Win2K than under XP, according to superficial tests we performed recently.

[Steven_L_Intel1]

Tim, I don't think this is the case. Applications compiled with 8.1 do not themselves use noticeably more RAM than those compiled with other compilers. "Hogging" is also not an appopriate term here.

I can certainly understand that Windows XP may manage virtual memory differently than Windows 2000, and may reserve more to itself. Some time spent in the Performance Monitor section of Task Manager might help understand what is going on. If the CPU is not being used 100%, and there is a lot of disk I/O, then it may be that the system is at the threshold of where more RAM would be helpful.

What I have noticed is that applications that are CPU-bound and don't call back into the OS do tend to make system performance sluggish on XP, evem with plenty of RAM.

[rahzan]

Martien,

I have seen the super slow openning of ms-word, and in my case it hasNOT been while running any fortran or concole app. Because I only use ms-wordprocessor to read the rare docuemnts received from others, I never bothered tracking it down.

I suggest you put on a more recent version of ms-office and be sure to put on all its service packs which are not well advertised.

You may want to check out these links:

http://support.microsoft.com/default.aspx?scid=kb;en-us;q262530

http://word.mvps.org/FAQs/AppErrors/ProbsOpeningWord.htm

hopethis helps.