I was having high consumptions of cpu. How could I know what was being executed at that time of high cpu consumption?

There really isn't a way to find out after the fact. If the issue happened at about 0:00 UTC on July 1, 2012, it's possible you hit a bug caused by the leap second being added to UTC to account for the slowing rotation of the Earth.

- http://serverfault.com/questions/403732/anyone-else-experiencing-high-rates-of-linux-server-crashes-today

-Tim

Edit: If you did in fact hit this bug, rebooting should clear you right up.

_________________
'If debugging is the process of removing bugs, then programming must be the process of putting them in.' //Edsger Dijkstra
'Nothing is withheld from us which we have conceived to do.' | 'Do things that have never been done.' //Russell Kirsch

If you don't mind a bit of scripting, you can cron something every minute or so using something like

top -bn1

within the script and then parse through the resulting text, writing to a file when the script finds something interesting to you. I prefer Python, so I might use

os.popen('top -bn1')

and parse the stdout result of os.popen() as needed.

James