my coalescer on ML kit: bad
Stephen Weeks
sweeks@intertrust.com
Tue, 11 May 1999 12:04:06 -0700 (PDT)
> old coalescer new coalescer
> number of chunks 11,425 7,677
> number of trampolines 217,944,056 206,952,722
> number of returns 220,922,989 220,945,534
> number of inter-chunk returns 157,022,980 103,291,304
> number of limit checks 119,171,837 119,188,003
> CPU time 164.34 165.45
>
> The number of inter-chunk returns went down by 52%, which is good. Why did
> the number of inter-chunk returns go down by so much when the number of
> trampolines went down hardly any? Is it really just luck, and almost all the
> old inter-chunk calls were still inter-chunk?
It's actually worse than you say. In order to keep the number of
trampolines up, the number of inter-chunk calls must have gone way up
(by about 45M) with the new coalescer. I base this conclusion on the
following equation.
trampolines = inter-chunk calls + inter-chunk returns
This may be due to some bias in the edges given as input
equivalence-graph.