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2:55:52
Kevslinger
I will be entering my third year of undergraduate study in the fall. Though the intermediate steps are unclear (Temple has some programs I may participate in which could extend my time there), the end goal is to enter a PhD program in some form of CS (right now Machine Learning / Natural Language Processing are the frontrunners for concentration).
3:05:21
beach
What cracauer is saying about GC is interesting. I don't understand the details because I don't know what SBCL does sufficiently well, but it will be interesting to see the performance of my planned SICL GC in comparison. Not imminent of course.
3:07:19
beach
It is also interesting to see what the plan for Clasp is. It is good that dead code will be possible to collect, but is live code going to be copied? I seem to remember some negative impact on cache performance for such things.
3:25:06
beach
This pool stuff sounds magic, but in the end you only have a linear memory, so the pool organization is going to have an influence as well I would imagine.
3:27:18
beach
Maybe one can now have any number of "holes" in the available memory and therefore manage any number of independent pools that can grow or shrink.
13:11:52
karlosz
beach: the sfa conversion from ssa is only a few lines of code, but it doesnt seem to alleviate the predecessor/input issue
13:14:35
karlosz
consider a constant prop algorithm that looks at a phi node and decides whether its output is a constant value or not
13:14:58
karlosz
by checking its executable inputs (aka inputs that are associated with predecessors marked executable)
13:15:33
beach
Well, it eliminates the predecessor order issue. How to adapt the algorithms is another matter. That could be a bit tricky.
13:16:24
karlosz
yeah. there needs to be a good way to look up the lexical variable produced by a particular branch
13:21:11
beach
I can't work like this. I need to look at the algorithm by myself, calmly, off line, and see whether I can see how to adapt it.
13:26:52
beach
Yes, I remember. Their value-numbering algorithm is the only algorithm I know that really needs SSA, and that fact makes it no good.
13:29:25
karlosz
not treating phi nodes specially means you throw out all the flow information contained in them
13:43:33
beach
Yeah, well, the paper is from 1991, so they are probably referring to some abstract idea of "LISP".
13:50:15
beach
karlosz: I take it you are using the last one of the four algorithms presented in the paper?
13:54:54
karlosz
there are pdfs online, and it is a great book overall, especially the advanced topics
13:56:07
beach
I find that when real code is used, there is a lot of distraction about the limitations of the language.
14:00:16
karlosz
OK. Here is an excerpt of what his code looks like if you are concerned about language https://paste.gnome.org/pbdadk6lx
14:01:55
beach
Because it is known that there is no single representation of sets that make all operations fast. So I constantly find myself having to think about how those sets must be represented to make things fast.