Bytecode question: the send instruction

Alexandre Bergel bergel at iam.unibe.ch
Tue May 13 14:01:47 UTC 2003


Hello!

By reading the green book, I have some question related the send bytecode (page 210):
 - "Approximately every third instruction is a message send and sends requiring dictionary lookups occur every 6.667 bytecodes. Of the sends needing dictionary searches, 36.64% invoked primitives, and the rest resulted in the execution of a Smalltalk method which, along with process switches, accounted for a context switch every 6.50 bytecodes."
 - "... 78.92% are arithmetic and logical operations..."

This article was made in 1982, I would like to know it these proportion are still equivalent nowadays.

A bit related to this, what is the effect of the method cache? In the average, what is the % of the method found in the cache?

I heard once that only 1/10th of the message send are really polymorphic, and the rest is mono-morphic. 

Cheers,
Alexandre

-- 
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Alexandre Bergel  http://www.iam.unibe.ch/~bergel
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