My apologies if this has been described somewhere but what is MUT time? Also, isn't 30% GC a bit high? This is something that totally surprised me when I first saw it as my program was spending 60-70% on GC. Is there a good low % number that should be used as a benchmark? Thanks, Joel On Jan 5, 2006, at 10:01 AM, Simon Marlow wrote:
INIT time 0.00s ( 0.00s elapsed) MUT time 2.48s ( 2.58s elapsed) GC time 1.08s ( 1.08s elapsed) EXIT time 0.00s ( 0.00s elapsed) Total time 3.56s ( 3.65s elapsed)
%GC time 30.3% (29.5% elapsed)
Alloc rate 68,007,748 bytes per MUT second
Productivity 69.7% of total user, 67.9% of total elapsed
My hypothesis is that when we give each thread its own memory block, all the thread stacks occupy the same cache lines and we end up with a lot more cache misses (notice it's the MUT time that increased, not the GC time).