After weeks of testing we deployed .NET 4.5 (upgraded from 4.0) on our ASP.NET production application. Site functionality is solid as our testing demonstrated. There ARE differences though that we are working thru that may prompt other questions.
I have a question about the garbage collection performance monitoring counters. Prior to 4.5, my rule of thumb has been that there are 10x gen1 collections as gen2, and 10x gen0 collections as gen1. Based on this, a healthy snapshot of GC counters would be
gen0 1200
gen1 150
gen2 20
Now that 4.5 is running the 10x rule doesn’t seem to apply anymore. I’m seeing numbers more like this (taken at roughly the same time of day as before):
gen0 850
gen1 650
gen2 400
I am also seeing more ‘induced GC’ than before.
In addition, ‘bytes in all heeps’ and ‘cache entries’ are much lower, and yet our site is very responsive and CPU is nice and low, as it was before.
When we deployed 4.5 we made NO changes to our 4.0 application.
I don’t want to solve a problem that isn’t here, but it appears ‘normal’ has changed. Does this make sense?
This was a false alarm. After two weeks of monitoring after the 4.5 migration the GC counters do indeed follow the original pattern – gen0 ~10x gen1 ~10x gen2.
So all is well! Now to get to the bottom of why compilations don’t appear… 🙂