Re: Who uses clapack?notions to pastures.

From: Gordon Sande (g.sande_at_worldnet.att.net)
Date: 12/12/04 

Date: Sun, 12 Dec 2004 20:51:46 GMT

Jentje Goslinga wrote:
>
>
> Gerry Thomas wrote:
>
>> "Jentje Goslinga" <goslinga@telus.net> wrote in message
>> news:41BA59EC.2050208@telus.net...

[snip]

>
> No understanding of how computers function which is
> apparent from clever attempts at optimization such as:
>
> I1 = I+1
>
> Let's say the compiler already has "I" in a register
> and now has to allocate a stack variable (in cache memory)
> to hold an extra variable and move this integer from
> the stack to save a single cycle a few times.
>

Perhaps what they were optimizing was the number of compiler
error messages. It is well known that programs are much more
efficient when the number of compiler error messages is zero.

When dinosaurs were current the statement

   do 10 i = 1, n + 1

drew a diagnostic about bad syntax so the result was

   n1 = n + 1
   do 10 i = 1, n1

The underlying cause was an attempt by the compiler writers, in their
role as language designers, to make use of the machines which they had
access to. Those machines had vary fast caches as the memory and
processor speeds were about the same. No extra cost for memory latency
as the cache did not get in the way. The cache was quite inexpensive
as it consisted of a length of copper wire on the backplane.

[snip]

>
> Jentje Goslinga
>

Relevant Pages

  • Re: Who uses clapack?notions to pastures.
    ... Jentje Goslinga wrote: ... > apparent from clever attempts at optimization such as: ... as the cache did not get in the way. ...
    (comp.lang.fortran)
  • Re: websitedesign.co.uk up for auction
    ... When you are looking for a key phrase and a site that comes up with either some of the words or not all of the words it will say that the words have links to the page using those word/s when you check the cache. ... Yeah, brass, crystal, fancy, Victorian home decor and stuff. ... If you have the stock in inventory why not do both internet marketing and brick and mortar. ...
    (alt.internet.search-engines)
  • Re: websitedesign.co.uk up for auction
    ... and you check the cache it has that the page has links pointing to it for ... that phrase if you don't have the word listed, ... both internet marketing and brick and mortar. ...
    (alt.internet.search-engines)
  • Re: Purchasing the correct hardware: dual-core intel? Big cache?
    ... Depending on where you got the PostgreSQL, was it in binary form or source. ... While a bigger cache may help, as may dual core CPU's, or faster CPU's. ... Poor optimization causes a CPU to chug along, ... MailScanner thanks transtec Computers for their support. ...
    (freebsd-questions)
  • Re: Anyone using an Opteron 165 SK939 as a desktop processor?
    ... from a higher clockspeed than the extra cache. ... the Opteron CPUs (normally way out of price range or on a 940 socket) ... pair of 466 Celerons at 525mhz purely using software tweaks and standard ...
    (uk.comp.homebuilt)