Trace overhead

[Brett Robichaud]

Does anyone know what kind of overhead is caused by enabling tracing in an
ASP.NET 1.1 app?

On my production servers I'd like to leave it enabled so I can view
trace.axd to get a feel for the activity and problems on my site, I'd leave
pageOutput="false". But I'm wondering what kind of extra load my servers
experience due to this. Any ideas?

I'm also curious how bumping up the requestLimit increases the overhead?
I'd like to use a value of 250 or more.

I haven't found any documentation on the overhead associated with tracing.

-Brett-

 

[Jeffrey Palermo]

The performance hit is considerable, but it won't render the app unusable.
In fact, if your server fully loaded, I doubt the users would even notice.
I've done performance testing with and without tracing, and tracing cuts my
requests/sec in half, but my normal usage is way lower than my stress
testing usage, so I wouldn't worry. Because you are considering tracing in
production, I'm assuming that this isn't a "if the site is slow, we lose $5
billion" application. After your 250 request threshold is reached, the
performance will increase again because tracing will be turned off.

Jeffrey Palermo

 

[Brett Robichaud]

Performance on our site is definitely not the top concern, just the standard
'it should be reasonably fast'.

Thanks for the insight on your own performance testing.

I'm curious about your last comment. It was my understanding that the trace
request threshold was a rolling FIFO cache. You state that after 250
requests (assuming I set the limit at 250) it would stop tracing. Is this
true? I assumed it would just throw the top requests off the cache and keep
tracing. If what you're saying is true then the usefulness of it for me is
significantly reduced.

-Brett-

 

[Jeffrey Palermo]

Yes, your fears are true. Test it out for yourself. Set the trace limit to
2, then hit your app. Only the first 2 requests will show up on trace.axd.
After the trace limit, it stops tracing.

Jeffrey Palermo

 

[Brett Robichaud]

Wow, that is hugely dissapointing. To me that severly limits the usefulness
of tracing.

I am surprised there isn't at least an option to enable it to act as a FIFO
cache.

-Brett-