Nagios Profiler Changes

[Steven D. Morrey]

Hi Everyone,

As you know I've been hard at work creating a profiler for nagios that is simple, flexible, extensible, fast and above all accurate.

My initial design was to create a collection of global timers gt_* and global odometers go_* variables that could then be written out to status.dat one by one.
This worked ok but became quickly unwieldy for obvious reasons.

My next design was a linked list of objects containing the timer and the counter, as well as name or event type, this made extensibility a snap, but would have made a significant impact on speed since we would have to walk the list at best, and at worst do a strcmp on every single object every time we wanted to update a stat.  So this idea was discarded for the time being.

Finally I had a better idea.  Each event type is an integer and even though they aren't necessarily close together they would still be appropriate for an array index even if it's a sparse one.
So this is the new profiler design.

We have an object containing
elapsed time, counter, enabled

We have an array of these objects indexed by event type
profiler[event].counter++;

Then when we write it out to status.dat we have a very simple loop that looks to see if the event type is enabled for profiling and outputs it if it is.
The output looks like
PROFILE_COUNTER_EVENT_SERVICE_CHECK=100

Nagiostats then looks for the word PROFILE, and then for COUNTER or ELAPSED, then adds that to a linked list ala my second design, and outputs via mrtg or the normal nagiostats output.

The other major difference is what we are using to calculate time.
In the original design we just used time(), but later we decided we needed more resolution so we went to clock(), finally it was discovered that using clock would introduce a bug every 72 minutes and so now we just use gettimeofday
In the next version I may include clock() time as well but I thought that this would be sufficient for our needs.
Let me know what you think and I'll try to get a patch out ASAP.

Sincerely,
Steve


 NOTICE: This email message is for the sole use of the intended recipient(s) and may contain confidential and privileged information. Any unauthorized review, use, disclosure or distribution is prohibited. If you are not the intended recipient, please contact the sender by reply email and destroy all copies of the original message.



------------------------------------------------------------------------------
Crystal Reports - New Free Runtime and 30 Day Trial
Check out the new simplified licensing option that enables unlimited
royalty-free distribution of the report engine for externally facing 
server and web deployment.
http://p.sf.net/sfu/businessobjects