Re: [9fans] Rant (was Re: Plan9 and Ada95?)

Re: [9fans] Rant (was Re: Plan9 and Ada95?)

[bwc]

> Has anyone compared the efficiency of the code produced by GCC and the
> Plan 9 compiler?

I recently re-read Jim Gray's paper `The 5-minute Rule.'  It's interesting
to note that when he wrote the paper (1985) a meg of memory was $5K and a MIP
was $50K.  Now, by my calulations, a meg is about $0.50 and a mip is about
$0.30.

The economics of CS used to be:
	1) correctness of programs
	2) time efficiency
	3) space efficiency

Considering the changes in speed and memory, I assert that for all but
the most demanding case, only 1) is still a limited resource.

What do these economics say about optimizing compilers?

  Brantley Coile

Re[2]: [9fans] Rant (was Re: Plan9 and Ada95?)

[Matt]

>> Has anyone compared the efficiency of the code produced by GCC and the
>> Plan 9 compiler?

bbc> I recently re-read Jim Gray's paper `The 5-minute Rule.'  It's interesting
bbc> to note that when he wrote the paper (1985) a meg of memory was $5K and a MIP
bbc> was $50K.  Now, by my calulations, a meg is about $0.50 and a mip is about
bbc> $0.30.
the 1997 version of that paper is here :

http://ftp.research.microsoft.com/pub/TR/TR-97-33.doc

and here

http://research.microsoft.com/~gray/5_min_rule_SIGMOD.doc


bbc> The economics of CS used to be:
bbc>         1) correctness of programs
bbc>         2) time efficiency
bbc>         3) space efficiency

bbc> Considering the changes in speed and memory, I assert that for all but
bbc> the most demanding case, only 1) is still a limited resource.

bbc> What do these economics say about optimizing compilers?


I'm no compiler expert but it is my assertion that the popularity of
scripted languages indicates that the running time of many many
programs is not significant. Such that 1) can probably save you more
time/money in the long run anyway.

If the world has got time for transparent menus and java applets then
it can suffer not unrolling every loop and using registers when
possible.

My first encounter with optimizing compilers was ms C (ver 3 I think)
It used to do the ultimate optimization and just silently drop your
code into the bit bucket anyway!

Re: [9fans] Rant (was Re: Plan9 and Ada95?)

[Noah Diewald]

On Thu, Nov 08, 2001 at 12:58:07PM +0000, Matt wrote:
> If the world has got time for transparent menus and java applets then
> it can suffer not unrolling every loop and using registers when
> possible.

I've implemented a transparent menu in this email.  See below.

Re: [9fans] Rant (was Re: Plan9 and Ada95?)

[Taj Khattra]

On Thu, Nov 08, 2001 at 07:30:39AM -0500, bwc@borf.com wrote:
>
> What do these economics say about optimizing compilers?
>

here's a link to proebsting's "law" of compiler optimization

	http://research.microsoft.com/~toddpro/papers/law.htm

and some related observations

	http://www.cs.virginia.edu/~jks6b/on_proebstings_law.pdf
	http://www.cs.umd.edu/~pugh/IsCodeOptimizationRelevant.pdf

-taj