[gambit-list] Help With Memory
Marc Feeley
feeley at iro.umontreal.ca
Fri Sep 26 11:40:18 EDT 2008
On 26-Sep-08, at 11:29 AM, Bradley Lucier wrote:
>
> On Sep 26, 2008, at 9:23 AM, Marc Feeley wrote:
>
>> Another point I want to make is that Cheney on the MTA give you
>> "free" call/cc only after paying a premium on other things, namely
>> stack-like behaving function calls and tail-calls. Because typical
>> code, and even realistic call/cc intensive code such as a thread
>> system, do much more of these other things than calling call/cc,
>> the overall performance of the system is suboptimal in general.
>> With the latest set of benchmark results on 51 benchmark programs,
>> in "r6rs" mode Chicken is 2.7 times slower than Gambit on average
>> (geometric mean). That's the cost of "free" call/cc.
>
> Marc:
>
> I'd just like to point out here that, as I'm sure you're aware,
> there are many different implementation decisions that are made in
> each of Chicken and Gambit and it is unlikely that any speed
> difference between the two can be attributed to any single design
> decision. The choice of "free" call/cc via Cheney on the MTA may,
> indeed, be an implementation choice that affects adversely nearly
> all other aspects of an implementation (which I doubt), but that
> could only be determined after quite a bit of analysis.
>
> Brad
Yes (of course). I did not mean that the cost of Cheney on the MTA is
"2.7 times slower code on average". I meant that a part of that
factor of 2.7 was due to Cheney on the MTA. I think it is a
substantial part, but the exact amount would require a lot of
analysis... enough to generate several interesting research papers!
Marc
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