On 05.02.2016 00:06, Matthias Bussonnier wrote:
On Feb 4, 2016, at 08:22, Sven R. Kunze <srku...@mail.de> wrote:
On 04.02.2016 16:57, Matthias Bussonnier wrote:
On Feb 3, 2016, at 13:22, Yury Selivanov <yselivanov...@gmail.com> wrote:
An ideal way would be to calculate a hit/miss ratio over time
for each cached opcode, but that would be an expensive
calculation.
Do you mean like a sliding windows ?
Otherwise if you just want a let's say 20% miss threshold, you increment by 1
on hit,
and decrement by 4 on miss.
Division is expensive.
I'm not speaking about division here.
if you +M / -N the counter will decrease in average only if the hit/miss ratio
is below N/(M+N), but you do not need to do the division.
Then you deoptimize only if you get < 0.
I see but it looks still more complicated. :)
On Feb 3, 2016, at 13:37, Sven R. Kunze <srku...@mail.de> wrote:
On 03.02.2016 22:22, Yury Selivanov wrote:
One way of tackling this is to give each optimized opcode
a counter for hit/misses. When we have a "hit" we increment
that counter, when it's a miss, we decrement it.
Within a given range, I suppose. Like:
c = min(c+1, 100)
Min might be overkill, maybe you can use a or mask, to limit the windows range
to 256 consecutive call ?
Sure, that is how I would have written it in Python. But I would suggest an AND
mask. ;-)
Sure, implementation detail I would say. Should not write emails before
breakfast...
;-)
The other problem, with the mask, is if your increment hit 256 you wrap around
back to 0
where it deoptimize (which is not what you want), so you might need to not mask
the
sign bit and deoptimize only on a certain negative threshold.
Does it make sens ?
Definitely. I am curious about the actual implementation of this idea.
Best,
Sven
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