Unexplained Jumps In Response Time "Fixed" By Disabling Tiered Compilation

James Lent jlent at tivo.com
Fri May 27 13:21:45 UTC 2016

Thanks for the suggestion.

I did turn that option on.  I should have mentioned it in my original post.  There is typically some JIT activity at the time of the jump, but, no more or less than "usual" (as far as I could tell).  I was hoping to see either a lot of activity or some low level Lucene method get recompiled or made not entrant in the minute between the last "good" response time and the first "bad" response time.  I could not see a pattern.

On 25/05/16 15:33, James Lent wrote:
  . . .

I then tried turning off Tiered Compilation (without changing the
default Code Cache size) in dev and the problem went away.  Of course it
is hard to prove a negative.  We are now testing in production with good
results (over 40 hours of good performance).

Any thoughts?  I realize this is not much to go on, but, I thought I
would report my issue just in case you get other reports like this and
you start to see a pattern.

Have you tried turning on listing compiles with -XX:+PrintCompilation?

It would be very interesting to see what sort of compile activity is
going on around the time that the jumps in response times occur. A
comparison between +TieredCompilation and -ToetredCompilation might be
very informative.


Andrew Dinn

James Lent
Senior Software Engineer

A TiVo Company

jlent at digitalsmiths.com<mailto:jlent at digitalsmiths.com>  | office 919.460.4747


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