<div dir="ltr"><br><div class="gmail_extra"><br><div class="gmail_quote">On Fri, Dec 18, 2015 at 11:25 PM, Robert Withers <span dir="ltr"><<a href="mailto:robert.w.withers@gmail.com" target="_blank">robert.w.withers@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> <br>
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<div>On 12/19/2015 02:09 AM, Eliot Miranda
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<div>Hi Robert,<br>
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<div>On Dec 18, 2015, at 9:51 PM, Robert Withers <<a href="mailto:robert.w.withers@gmail.com" target="_blank"></a><a href="mailto:robert.w.withers@gmail.com" target="_blank">robert.w.withers@gmail.com</a>>
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<div><span>Eliot, what does Sista do and how is that
accomplished? </span></div>
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Run-time adaptive optimisation via an SSA-based image-level
bytecode-to-bytecode inlining compiler. See
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<div><a href="http://www.mirandabanda.org/cogblog/on-line-papers-and-presentations/" target="_blank">http://www.mirandabanda.org/cogblog/on-line-papers-and-presentations/</a></div>
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<div><span>It sounds like a next level kind of system.
Does it compare to what other JITs are doing in
various VMs?</span><br>
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Yes it does. Clément recently attended a workshop at Google
and found that Sista is very similar in the kinds of
optimisations it performs to V8 and Dart. The key research
funding will be how close the performance of targeting
stack-oriented bytecode that the Cog JIT converts to
register-based code can be made to JITs that directly target
register-based machine code.</div>
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This sounds like you are saying that Sista performs better or more
naturally with stack-oriented bytecode. If you wouldn't mind taking
the time to explore it with us, what's the difference between
stack-oriented and register-based code, such that Sista would be
different between them? I'm off to read some.<br></div></blockquote><div><br></div><div>I'd rather not. That's something there's lots of papers on, and I'm not sure it's really important that I explain. Yoiu can inform yourself, and the Sista talks I pointed to at least mention the topic. I will say that our thesis is that we can generate efficient register-based machine code from stack-oriented bytecode, and that's one of the things we're trying to demonstrate with Sista.</div><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div text="#000000" bgcolor="#FFFFFF">
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<div><span style="background-color:rgba(255,255,255,0)">_,,,^..^,,,_
(phone)</span></div>
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<span>thank you,</span><br>
<span>robert</span><br>
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<span>. .. ...
^,^</span><br>
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<span>On 12/18/2015 11:11 PM, Eliot Miranda wrote:</span><br>
<blockquote type="cite"><span> Further, please keep the
original Smalltalk non-primitive implementation
around do that when we deliver Sista we can see how
well we stack up against C.</span><br>
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<blockquote type="cite"><span>_,,,^..^,,,_ (phone)</span><br>
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<blockquote type="cite"><span>On Dec 18, 2015, at 5:59
PM, David T. Lewis <<a href="mailto:lewis@mail.msen.com" target="_blank">lewis@mail.msen.com</a>>
wrote:</span><br>
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<blockquote type="cite"><span>On Fri, Dec 18, 2015
at 08:13:00PM -0500, Robert Withers wrote:</span><br>
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<blockquote type="cite"><span>On 12/18/2015 08:07
PM, David T. Lewis wrote:</span><br>
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<blockquote type="cite"><span>If you are
implementing your algorithm from scratch, then
it would be</span><br>
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<blockquote type="cite"><span>nice if it could be
done in Smalltalk, because that means we can
all</span><br>
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<blockquote type="cite"><span>read it, play with
it in the image, and write unit tests to
validate and</span><br>
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<blockquote type="cite"><span>document its
behavior. We can figure out the translation to
C afterwords,</span><br>
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<blockquote type="cite"><span>once you have a good
implementation in Smalltalk (and yes I will
help</span><br>
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<blockquote type="cite"><span>with that).</span><br>
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<blockquote type="cite"><span>I have a smalltalk
implmentation that came from Google Java code
and is</span><br>
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<blockquote type="cite"><span>fully implemented in
squeak/pharo. I am intermittently fixing byte</span><br>
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<blockquote type="cite"><span>mutations in the
payload, so it is working to a degree. Check out
the</span><br>
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<blockquote type="cite"><span>classes GenericGF,
GenericGFPoly and GaloisField to see the
insides.</span><br>
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<blockquote type="cite"><span>FECEncoder and
FECDecoder are calling the galoisField which
builds a</span><br>
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<blockquote type="cite"><span>ReedSolomon Decoder.
That last is where the error detection occurs.</span><br>
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<blockquote type="cite"><span>Thank you all very
much for looking out!</span><br>
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<blockquote type="cite"><span>I guess my suggestion
would be that once you have a fairly good working</span><br>
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<blockquote type="cite"><span>implementation that you
are comfortable with from a functional point of</span><br>
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<blockquote type="cite"><span>view, then let's look at
which methods in that implementation would benefit</span><br>
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<blockquote type="cite"><span>from being translated to
primitives in C. It would be especially good if</span><br>
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<blockquote type="cite"><span>you can run a profiler
on your Smalltalk implementation and see where the</span><br>
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<blockquote type="cite"><span>time is being spent.
Those would be the things we would want to turn
into</span><br>
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<blockquote type="cite"><span>primitives. But first
things first, let's get it working 100% (not "to a</span><br>
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<blockquote type="cite"><span>degree") and then we can
do the translation to primitives.</span><br>
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<blockquote type="cite"><span>Dave</span><br>
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<span>-- </span><br>
<span>. .. .. ^,^ robert</span><br>
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<div>-- <br>
<div align="left">. .. .. ^,^ robert
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<br></blockquote></div><br><br clear="all"><div><br></div>-- <br><div class="gmail_signature"><div dir="ltr"><div><span style="font-size:small;border-collapse:separate"><div>_,,,^..^,,,_<br></div><div>best, Eliot</div></span></div></div></div>
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