String concatenation tweaks

Maurizio Cimadamore maurizio.cimadamore at
Thu Jun 4 17:50:04 UTC 2015

On 04/06/15 17:23, Aleksey Shipilev wrote:
> While it maybe an interesting experiment to try, the performance
> engineering experience tells me to focus on the parts that are relevant,
> rather than doing every experiment you can come up with, otherwise you
> will never ever un-bury yourself from the performance work:)
I don't think this is *any* experiment you can come up with - it's the 
very foundation for all the JEP work. For the JEP to be viable you need 
to prove that whatever technique you come up with, it would be almost in 
the same ballpark as the one implemented in javac. If the numbers are 
the same, then it's mostly an argument of whether we want to open up the 
machinery vs. keeping it buried in javac (and the future maintenance 
cost for any BSM added). But what if the numbers are not the same?

Put in other words, if the natively written javac impl was 10x faster 
with no startup cost (I'm obviously making things up), wouldn't that 
mean the very death of this JEP?

Or, again put in other words, as you have a column in your benchmark 
called   'BASELINE', I think it'd be nice to also have a column called 
'LOWER_BOUND', and see how the various solutions would compare against it.


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