Old:
while (tickNextIdle < curTick)
tickNextIdle += clock;
New:
if (tickNextIdle < curTick)
tickNextIdle = (curTick / clock) * clock + clock;
We actually went back and forth about this. The question is, when is the
divide better than the loop? We never profiled the code, so we didn't
have evidence that one was better than the other. It seems that you're
saying that the divide is better. We were even thinking that it might
make sense to try the add say four times, and do the multiply if it didn't
work out. (That way busy busses only pay the cost of an add or two, and
slow busses escape with a divide/multiply.) Would you be willing to try
somethign like this?
if (tickNextIdle < curTick)
tickNextIdle += clock
if (tickNextIdle < curTick)
tickNextIdle += clock
if (tickNextIdle < curTick)
tickNextIdle += clock
if (tickNextIdle < curTick)
tickNextIdle += clock
if (tickNextIdle < curTick)
tickNextIdle = (curTick / clock) * clock + clock;
It really has been quite a while since anyone in the core group has
profiled M5, so we'd appreciate this sort of help from people! If you can
identify something that's slow and what fraction of the total execution it
accounts for, that'd be fantastic. Suggestions on improvement are an
added bonus. A statement about what kind of speedup is achieved is icing
on the cake.
Thanks,
Nate
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