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top command

 
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# 1  
Old 05-11-2005
top command
hi guys,
i am having a dual cpu xeon machine.
i came to know that i can view the performance by giving top command.
but top command shows only the usage of one cpu in percentage
while the process are using more than 100% usage in the list .
can i know separately the usage of cpus.
can you guys suggest any help if this question means something.
# 2  
Old 05-11-2005
What is the OS thats run on your system. You can install sysstat on Linux and use sar command to view the CPU usage. Top does not seem to show CPU usage properly. It shows 49.9% for a process even when that process is using more than that
# 3  
Old 05-11-2005
doing 'man top' yields [amoung others]
Quote:
Originally Posted by man top
CPU percentage is calculated as a fraction of total avail-
able computing resources. Hence on a multiprocessor machine
a single threaded process can never consume cpu time in
excess of 1 divided by the number of processors. For exam-
ple, on a 4 processor machine, a single threaded process
will never show a cpu percentage higher than 25%. The CPU
percentage column will always total approximately 100,
regardless of the number of processors.
# 4  
Old 05-11-2005
Thats true when the process is single threaded as it is run on one CPU. In my case, i have a multi threaded java code. However, if i use sar with some switches to see a process CPU usage, it was showing properly.
# 5  
Old 05-11-2005
right - that was the disclaimer in the 'man' pages of the top version I've got here - it might have changed in the later version of 'top'.

And how 'bout 'prstat'?
# 6  
Old 05-11-2005
This was on Redhat linux only and also on only some machines. There is some inconsistency. I am not sure if Linux has prstat.However, I did not see any such issue with top on HP-UX, topas on AIX and prstat and top on solaris. I am not sure what OS bijuhpd is using and his process is single threaded or multi-threaded..
 
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