Re: [pop-dev] Go - a new language from Google

[Jim Whitehead II <jnwhiteh@xxxxxxxxx>]

On Thu, Nov 12, 2009 at 7:11 PM, Tom Locke <tom@xxxxxxxxxxxx> wrote:
>> KRoC continues to win out against the competition
>
> I may well be wildly off here, but I seem to remember that the KRoC compiler
> improves the performance of the context switch by arranging for the
> registers to hold nothing important at the point in the code where the
> switch occurs. Thus eliminating the need for the registers to be
> saved/restored.
>
> If I am remembering correctly on this point, it strikes me as very
> misleading to compare only context switch times. The overhead seems to have
> been moved to the computation that the process is performing, which can no
> longer take full advantage of the register set.

It is, as has already been mentioned.  Commstime is a very limited
benchmark that shows one thing, and given how new the language is, I
haven't had a time to implement any of more realistic benchmarks in
the language.  That's my work for tomorrow =).

> It's easy to win micro-benchmark games if you put all of your focus on the
> micro-benchmark in question (e.g. on reducing context-switch overhead).
> Perhaps this is what Adam was getting at.

Indeed, I'm sure it was part of what he was suggesting.

> From what (little!) I understand, some of the biggest wins in compiler
> optimisation come from making good use of the registers. For example I've
> heard it said that a lot of effort is made to inline function calls, not
> because of the call overhead, but because you then get to really spread out
> and use all the registers. Would KRoCs strategy of having the registers
> empty at sync points cause havoc with this kind of optimisation?
>
> Please take all this chiefly as questions - I am well outside my comfort
> zone here : )
>
> Tom
>
>