[Vm-dev] CogVM performance

Esteban Lorenzano estebanlm at gmail.com
Sat May 16 15:14:27 UTC 2015


> On 16 May 2015, at 17:08, Levente Uzonyi <leves at elte.hu> wrote:
> 
> Hi All,
> 
> I saw that some of my benchmarks produce different results when running on PharoVM instead of CogVM, and I was wondering why. I ran #tinyBenchmarks from the same image on both VMs and the results were surprising:
> 
> "CogVM 3343" '904593639 bytecodes/sec; 46368169 sends/sec'
> "Pharo vm50" '941176470 bytecodes/sec; 120698445 sends/sec'
> 
> Slightly more bytecodes, and a lot more sends. I tried playing with compiler flags, but with no luck, so I came to the conclusion that the difference comes from somewhere else. I checked where the PharoVM was forked from CogVM (somewhere around 2014-06-10), so I downloaded a version of CogVM from around that time: CogVM 3048.
> 
> And the results are '932604735 bytecodes/sec; 118660385 sends/sec'.
> 
> Somewhere between 3048 and 3343 the performance has dropped significantly (sends/sec). Note that this is not something that's only visible in micro benchmarks.
> 
> Does anyone know why?

It has to be a flags issue. 
btw… We did not fork… I branched to work on spur and I still didn’t get back to trunk, in the mean time we just incorporated to trunk minor bugfixes :)


> 
> 
> Levente



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