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Re: Experiences with assq list and guile-log

From: Nala Ginrut
Subject: Re: Experiences with assq list and guile-log
Date: Sun, 15 Apr 2012 22:35:33 +0800

hi Stefan! I saw your guile-log based on Guile got good efficiency!
But I'm not sure what the "log" mean, could it possible be an
efficient logger for a server?
If it does, I plan to use it in my server project. My logger module is
very ugly before optimization.

On Sun, Apr 15, 2012 at 7:54 PM, Stefan Israelsson Tampe
<address@hidden> wrote:
> Hi,
> I've looked at one benchmark for the einstein case. (some numbers are from
> my memory)
> compiled prolog
> 12-14ms
> guile-log, stack-based, with added vm ops
> 30-40ms
> kanren, compiled chicken
> ~250ms
> guile-log, stack based,
> 250ms
> guile-log, assq-based
> 500ms
> kanren on guile
> 2000ms
> kanren on guile-log assq based
> 2000ms
> kanren on guile-log replacing the assq whith a functional lookup treee
> 1500ms
> kanren on guile-log stack based
> 300ms
> Note
> 1. kanren implementation on guile-log does not contain all
> of plain kanrens optimisations for assq state. This is on my TODO.
> 2. If we add vm ops then assq or tree based state management can be brough
> down
> to around chickens 250ms but I would expect the stack based version to go
> down
> to 20-30ms and naitvie compilation or JIT would bring it down to 12-16ms if
> we usa a stack for
> lambdas as well assq based one would stay an 250ms cause it is inherent in
> the datastructures.
> 3. Note that this is numbers for just one use case. As discussed earlier
> other use-cases may lead
> to other conclusions.
> 4. I also look forward to test Marks HAMT implementation in the future.
> On my TODO list now are.
> 1. Make sure to be able to use multiple stacks and make them resizable
> 2. With this I can start implementing multithreading support.
> 3. A retake on VM operations.
> 4. Making it possible to allocate a continuation lambda or a failure lambda
> on the stack.
> for 4, I could introduce my idea.
> The main problem here is that you may want to move the continuation from the
> stack to the heap
> in order to be able to resore a state. In order to do this I would change
> the representation of  sk
> functions and fk functions to be pointers to the actial functional object
> and make sure to never store
> the direct function inside for example a lambda. This means that at a unwind
> where we know that the
> lambda maight be referenced via a state storage variable we copy the
> function, and set the reference object
> to the new location. The reference object is unisized and small and could
> probably be allocated from the heap
> or be preaalocated and referensed on a stack and possible be replaced by a
> freshly allocated variable or cons
> cell fro the heap. This means that for example the einstein example will
> never allocate memory from the heap
> just use the internal stacks. The question is if it's worth it. My
> experience is that this will gain you maybe a factor
> of 2 or 3. Not especially much and to the price of a lot of complexity in
> order to make it safe.
> Ok, that's it from my Sunday Sunny thinkage,
> Have fun,
> Stefan

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