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Old 03-28-2006, 01:55 AM   #1
yumener
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why linux got very slow after runing computation intensive program?


Hi, I found that after I used Matlab in Linux to run some
computation intensive program(use 80% memo), the whole system
became slow. Even after I quit Matlab, the system can not be
compared with a fresh rebooted one.

Can anybody explain this phenomenon? I was thinking that
after running any program (unless memory leakage), system
should recover to the prevous status. So if I quit all
the programs I was running, the system performance should
be the same with a freshly rebooted one.

thanks!
 
Old 03-28-2006, 02:38 AM   #2
Agrouf
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Use the free and the ps command before and after matlab. Post the output.
 
Old 03-28-2006, 05:08 AM   #3
AwesomeMachine
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Goto sourceforge.net and search for "ramdefrag". Get that and install it. Then, when all the memory gets clogged up, run it.
 
Old 03-28-2006, 09:15 AM   #4
victorh
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One reason I've experienced is that when you run a program that needs a lot of RAM then the other programs are forced to go from RAM to Swap memory. Then when you finished and quit the program that is using most of the RAM, this memory is freed and available, but the other programs continue in the Swap memory area, therefore they run slower. There must be a way so that these programs can use again the RAM, maybe somebody knows a trick but for now I reinitialize these programs and things are normal again.
 
Old 03-28-2006, 12:41 PM   #5
yumener
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this one is good.

Quote:
Originally Posted by AwesomeMachine
Goto sourceforge.net and search for "ramdefrag". Get that and install it. Then, when all the memory gets clogged up, run it.
 
Old 03-29-2006, 01:28 AM   #6
khaleel5000
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does it reaally work?
 
Old 03-29-2006, 10:40 AM   #7
geeman2.0
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I'd also check out the top command after closing matlab to see if it's leaving any spinning processes running in the background.

This happens to me all the time with wine.
 
Old 03-29-2006, 11:45 PM   #8
AwesomeMachine
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I've used ramdefrag. It seems to work.
 
Old 03-29-2006, 11:46 PM   #9
AwesomeMachine
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I've used ramdefrag. It works.
 
Old 03-31-2006, 04:06 AM   #10
yumener
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Yes, it works.
ramdefrag will also show the "speed index" before
and after degragment. I do have great speed
enhancement after use ramdefrag.

I use top, and it tells me nothing.

of course, perhaps RAM fragment is only one cause
of decreased systerm performance. There maybe
other cause that ramdefrag will not work.

Quote:
Originally Posted by khaleel5000
does it reaally work?
 
Old 03-31-2006, 08:12 AM   #11
JaseP
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Another possibility is that either the program or some of its libraries are not getting out of memory...

Run top to find out what's hogging CPU cycles...
 
  


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