Truffle performance problems

[Dain Sundstrom]

Hi all,

I have been experimenting with Truffle in Presto for a day now and am confused by the performance I am seeing.  

My high level goal of this experiment is to figure out how I should structure data flow in my Truffle language.  Since, I am writing the language and the only user of that language together, I have a lot of options available to me.  Specifically, I'd like to figure out if I should take a vectorized approach, a row at a time approach, or some combination of both.  Which every solution is fastest, I'll make work in the code base.

To this end, I decided to take a top down approach to Truffle (mainly because I am confident the bottom expression bits will be fast).  I started with a very simple query hand-coded in Java:  

 double sum = 0;
 for (row in source) {
   if (row passes the filter) {
     sum += row.extendedprice * row.discount
   }
 }
 return sum;

When I run that on my machine using 5M rows of input (all in memory), it takes ~165ms using the Graal vm (1.7.0_45) with "-server" option on my laptop.  

With the performance baseline established, my plan was to start with a single node and then start breaking it apart into more nodes without making stuff slower. So, I wrapped this same code with a single Truffle RootNode.  When I execute the same code though the Truffle call, I get the same performance until the node is compiled.  Once the node is compiled, performance drops to ~260ms.  

Now, I understand using a single node is not the point of Truffle, but I would not expect such a massive performance drop off. At this point, I'm not sure if this is a worth while exercise at all.

You can find all of the code and instructions on running it here:

 https://github.com/dain/presto-truffle/tree/master

Any ideas or suggestions?

Thanks,

-dain



On a related note, if you leave the Truffle test running it eventually crashes with (https://gist.github.com/dain/c3a29eb81642c86f5072):

 Found illegal recursive call to HotSpotMethod<Utility.recursiveAppendNumber(StringBuffer, int, int, int)>, must annotate such calls with @CompilerDirectives.SlowPath!

I've also found "java.util.concurrent.ExecutionException: java.lang.IllegalStateException: Inlined graph is in invalid state" when executing a CallTarget in tight inner loops.