dtrace discuss - Jan 2010 - number of probes or times the probe triggered: which one impact more to the performance?

One script has 10k probes, but they are rarely triggered. Another script has
only one probe, but the probe triggered 10k per second. Which one will
impact the OS performance to a larger extent? In another word: performance
impact depends on the number of probes or times any probe triggered in a
second?

Thanks,
Daniel
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Hi Daniel,
> One script has 10k probes, but they are rarely triggered. Another 
> script has only one probe, but the probe triggered 10k per second. 
> Which one will impact the OS performance to a larger extent? In 
> another word: performance impact depends on the number of probes or 
> times any probe triggered in a second?
A short answer: performance will be affected more when probes are
being fired. Probe enablings that exist but aren''t fired are
essentially free.

If you haven''t yet read it you should read the 2004 Usenix
paper that the team did:

http://www.sun.com/bigadmin/content/dtrace/dtrace_usenix.pdf

Essential introductory reading for anyone who wants to understand
the basics of how DTrace does what it does.

Jon.