Profiling bugs in 6.8.1 and 6.6.1
daniel.is.fischer at web.de
Sun Nov 25 17:27:01 EST 2007
first let me remark that 6.8.1 is really remarkable, compiles faster and
produces faster executables than 6.6.1.
However, I have a problem with profiling, the time is always reported as 0.00
Sun Nov 25 22:58 2007 Time and Allocation Profiling Report (Final)
p28Master +RTS -P -hb -sstderr -RTS MMDataA
total time = 0.00 secs (0 ticks @ 20 ms)
total alloc = 1,313,421,840 bytes (excludes profiling overheads)
although it took more than 15 seconds:
INIT time 0.00s ( 0.00s elapsed)
MUT time 16.10s ( 16.41s elapsed)
GC time 10.76s ( 11.16s elapsed)
RP time 0.00s ( 0.00s elapsed)
PROF time 0.00s ( 0.00s elapsed)
EXIT time 0.00s ( 0.00s elapsed)
Total time 26.86s ( 27.57s elapsed)
Could that be caused by commenting out the lines
ifeq "$(GhcThreaded)" "YES"
SRC_HC_OPTS += -threaded
in compiler/Makefile.ghcbin ?
I did that because if I build ghc with -threaded, the times reported with
in ghci are rubbish (I have a linux 2.4.20 kernel, and the threads don't
support process-wide times; and no, I'm not likely to upgrade, SuSE 8.2 is
the only OS that ever worked properly for me).
If that's the cause, too bad, I'll have to revert to 6.4.2 for profiling :(
In 6.6.1, -O2 and -prof -auto-all don't work together well, I have a programme
where that combination of options results in an instant wrong output, while
-O1 -prof -auto-all
lead to the correct output calculated in 10 to 13 seconds.
If you're interested in that bug, I could send you the code, it's short
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