Lag sample in biographical profile is very wrong
In a recent heap profile I took the output of the biographical profiler is useless because of an incorrect LAG
sample.
BEGIN_SAMPLE 2.819970
VOID 2062560
LAG 18446744073709084864
USE 0
INHERENT_USE 0
DRAG 1152
END_SAMPLE 2.819970
This looks like an overflow error perhaps?
The way to reproduce it is
- Build ghc with
prof
flavour - Run biographical profiler on test for #9630 (closed)
eventlog-prof/stage1/bin/ghc T9630.hs -fforce-recomp -O2 +RTS -l -hb -hdId -hdIdInfo -hdGRefl
The value is so far out that the problem can probably be identified using gdb
or a few traces quite easily.