Re: [Valgrind-developers] valgrind: r12359 - in trunk: . memcheck/tests

[Florian K. <br...@ac...>]

On 02/12/2012 04:05 PM, Julian Seward wrote:
> 
> Great stuff, especially the numbers.
> 
>> Putting an upper bound on the number of nodes we allow sameIREXprs
>> to recurse into makes sense. But since proving equality was key
>> to fixing #287260 and recursing is not the norm I suggest to use
>> a large limit. The patch sets it to 100.
> 
> Having a natural aversion to global state, I'd have maybe preferred
> a depth limit, but no matter.  If we ever come to multithread the JIT
> we'll have way bigger problems to deal with.
> 

The depth is not as good a measure as is the number of nodes. A binary
tree of depth 4 can have anywhere between 4 nodes and 15 nodes. That
being said, the global state could still be avoided. But I left it as is
for now.

> Re the 100, this is my only concern.  I think that we could still get
> hit pretty hard in the worst case.
> 

I changed it down to 30 and committed it.
The numbers I had reported are deceiving. Although the number of
traversed nodes was <= 25 in all cases it can be much higher. I just ran
some proprietary application which showed max_nodes = 62   !!
Which only confirms what we already know: improving the perf bucket with
a larger variety of real apps would be a very good thing...

   Florian