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Old 01-12-2011, 03:40 AM   #1
sumedh.inamdar
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Question Confusing CPU utilization from top output


I am using a quad core CPU for my db server.

The top command shows one line about CPU utilization on top. It shows around 70-80%id (idle), which is cool, but the MySQL process shows %CPU column at a much higher value, more than 100%, sometimes more than 300%.

Is this a problem?

We are having issues with Mysql, it keeps crashing, want to find out if it's because of CPU getting hogged.

Here is the top output screen shot - http://tinypic.com/r/2mwffco/7
 
Old 01-12-2011, 04:32 PM   #2
r0b0
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If your CPU is quad core, a process can show up using up to 400% of CPU in top output. It is possible because of multi-threading - several threads of a single process can utilize more CPU cores. This by itself is no sign of any error.
 
Old 01-12-2011, 07:06 PM   #3
syg00
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You are comparing apples and oranges.
The summary number (in the header) is an average of all CPUs/cores - hit "1" (digit one, no quotes) while in top to see all CPUs individually. The separate process list is as @r0b0 pointed out a non-normalised usage. Use "H" to see threads listed.
Have a look at "man top".
 
  


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