From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matt Message-ID: <86580537899.20011108125807@proweb.co.uk> To: 9fans@cse.psu.edu Subject: Re[2]: [9fans] Rant (was Re: Plan9 and Ada95?) In-Reply-To: <20011108122852.B3F96199DD@mail.cse.psu.edu> References: <20011108122852.B3F96199DD@mail.cse.psu.edu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Date: Thu, 8 Nov 2001 12:58:07 +0000 Topicbox-Message-UUID: 19e880fa-eaca-11e9-9e20-41e7f4b1d025 >> 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!