C/C++ speed optimization bible/resources/pointers needed!

Peter K. wrote:
> Randy Yates <yates@ieee.org> writes:
>
>> Actually, if I wasn't running a GUI on my machine, and I had a more
>> robust UPS, and I was a more competent administrator, a reboot period
>> of one year (or more) would probably be well-within reach.
>
> A colleague of mine had bought a new computer and just before he
> turned the old one off, we checked the uptime.
>
> It read 444 days.
>
> Not up with the reliability of these guys: http://www.stratus.com/uptime/ftserver.htm
> where some machines have up-time measured in decades, but 444 days is
> still pretty impressive for a Mac.

A lot of people have quite poor uptime experiences with Stratus. While
the hardware protection is very effective, their OS used to be pretty
flaky (don't know about these days) and their reboot times could be over
an hour. We had cheap Compaq servers beating them hands down for uptime
in some telecoms applications.

Steve

"Jerry Avins" <jya@ieee.org> wrote in message
news:YqOdneYMtYNBLzfbnZ2dnUVZ_vzinZ2d@rcn.net...
> Walter Banks wrote:

> Since ISO/IEC 18037 provides for assembly code, that's a tautology. What's
> the ISO/IEC 18037 instruction for MAC?
Will you elaborate?
--
Wade Ward

Jerry Avins <jya@ieee.org> writes:
> What's the ISO/IEC 18037 instruction for MAC?

There isn't an "instruction", nor need there be, given that
the language doesn't consist of "instructions".

However, there's an example of a MAC in that standard.
Are you too blinkered to see it?

Phil
--
"Home taping is killing big business profits. We left this side blank
so you can help." -- Dead Kennedys, written upon the B-side of tapes of
/In God We Trust, Inc./.

"Androcles" <Engineer@hogwarts.physics> wrote in message
news:bavqi.16153$%v3.14614@fe3.news.blueyonder.co. uk...
>
> "Dr Ivan D. Reid" <Ivan.Reid@brunel.ac.uk> wrote in message
> news:slrnfakmvd.8th.Ivan.Reid@loki.brunel.ac.uk...
> : On Fri, 27 Jul 2007 04:44:59 GMT, jimp@specsol.spam.sux.com
> : <jimp@specsol.spam.sux.com>
> : wrote in <1d9on4-6ta.ln1@mail.specsol.com>:
> :
> : > Linux will be a LOT faster than Windows when doing number crunching.
> :
> : Really? I have two "identical" CPUs running seti@home.
>
>
> Do you really think some alien civilization is STUPID enough
> to broadcast their presence when we are now using cable and
> directional antennae for our own satellites?
> It's "sets": search for extra terrestrial stupidity, and only the stupid
> would participate.
>

But we haven't always done so. You're to quickly discounting (or ignoring)
the distance factor.

jimp@specsol.spam.sux.com writes:

>In sci.physics Michael Moroney <moroney@world.std.spaamtrap.com> wrote:

>> 30 days? That's nothing. I work with VMS systems, which frequently have
>> uptimes measured in years, as long as the electric utility, thunderstorms
>> and UPS's cooperate.

>VMS?

>You got TOPS-10 and RT-11 too?

Unlike TOPS-10 and RT-11, VMS is still actively being developed, runs on
Intel Itanium processors and is at version V8.3-1. It is no longer the
general purpose system you may remember it as, but is used in niche
applications, particularly "you bet your business on your data"
applications like the financial sector.

glen herrmannsfeldt <gah@ugcs.caltech.edu> writes:

>jimp@specsol.spam.sux.com wrote:

>(snip)
>>>30 days? That's nothing. I work with VMS systems, which frequently have
>>>uptimes measured in years, as long as the electric utility, thunderstorms
>>>and UPS's cooperate.

>> You got TOPS-10 and RT-11 too?

>Isn't TOPS-10 the one with the error message up-too-long?

I don't know of that, but a long time ago they had to make a change in
the format of the "Uptime" format on VMS. A company using VMS complained
that 3 digits for the "Days" field wasn't enough, it was printing stars.

Phil Carmody <thefatphil_demunged@yahoo.co.uk> writes:
> [...]
> Then again I tend to write C which maps 1-1 onto opcodes,
> so effectively I'm writing asm. Except that I don't have
> to write it for both PPC and Alpha, so I only need to do
> half of the work.

I don't understand - if you are effectively writing opcodes
in C, then why would you not have to rewrite it everytime
you retarget the processor?
--
% Randy Yates % "Midnight, on the water...
%% Fuquay-Varina, NC % I saw... the ocean's daughter."
%%% 919-577-9882 % 'Can't Get It Out Of My Head'
%%%% <yates@ieee.org> % *El Dorado*, Electric Light Orchestra
http://home.earthlink.net/~yatescr

On 28 juil, 03:59, Phil Carmody <thefatphil_demun...@yahoo.co.uk>
wrote:
> s...@microtec.net writes:
> > On 26 juil, 23:46, Gianni Mariani <gi3nos...@mariani.ws> wrote:
> > > s...@microtec.net wrote:
> > > > On 26 juil, 17:19, lunamoonm...@gmail.com wrote:
> > > ...
> > > > Your best bet with C/C++ is to get a fast computer. Optimization
> > > > is only nominal with these compilers.
>
> > > "nominal"? It's critical.
>
> > > I have no idea what you're alluding to but if you're trying to say that
> > > the optimizer is not one of the critical parts of a C++ compiler whenit
> > > comes to performance, you're very mistaken.
>
> > Of course, optimized C++ is way better than non optimized C.
>
> > But in order of code optimization, from worst to best, you have C++,
> > straight C, and Forth as best by far. C is simply no match for any
> > flavor of Forth for low level code optimization.
>
> > Simple fact of life.
>
> Can forth get a G4 to process more FPU instructions per tick than
> the processor is capable of handling? Given that I can get C to
> exactly match that bound, your forth can never be faster. Ever.
> Your claim is hollow.

I agree that writing efficient code with C is quite possible, as you
say. I found however that you have to constantly be careful of
how you write your code ( agreed that at some point, this tends
to fall into automatics when you do a lot of coding with this in
mind). Double checking low level code eventually becomes
second nature. The thing I found with Forth is that you don't
really need to be that attentive. You don't really need to watch
your coding.

> You obviously don't write good enough C.

I think I did fairly good programming, in assembly, C and
a few other languages, on micros and on mainframes.

André Michaud

In sci.physics Michael Moroney <moroney@world.std.spaamtrap.com> wrote:
> jimp@specsol.spam.sux.com writes:

> >In sci.physics Michael Moroney <moroney@world.std.spaamtrap.com> wrote:

> >> 30 days? That's nothing. I work with VMS systems, which frequently have
> >> uptimes measured in years, as long as the electric utility, thunderstorms
> >> and UPS's cooperate.

> >VMS?

> >You got TOPS-10 and RT-11 too?

> Unlike TOPS-10 and RT-11, VMS is still actively being developed, runs on
> Intel Itanium processors and is at version V8.3-1. It is no longer the
> general purpose system you may remember it as, but is used in niche
> applications, particularly "you bet your business on your data"
> applications like the financial sector.

Is this based on that DEC version on Unix DEC started pushing just before
they got bought up?

--
Jim Pennino

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"BobF" <no@thank.you> wrote in message
news:YJ6dnY4Xt_-B3zbbnZ2dnUVZ_h6vnZ2d@centurytel.net...
:
: "Androcles" <Engineer@hogwarts.physics> wrote in message
: news:bavqi.16153$%v3.14614@fe3.news.blueyonder.co. uk...
: >
: > "Dr Ivan D. Reid" <Ivan.Reid@brunel.ac.uk> wrote in message
: > news:slrnfakmvd.8th.Ivan.Reid@loki.brunel.ac.uk...
: > : On Fri, 27 Jul 2007 04:44:59 GMT, jimp@specsol.spam.sux.com
: > : <jimp@specsol.spam.sux.com>
: > : wrote in <1d9on4-6ta.ln1@mail.specsol.com>:
: > :
: > : > Linux will be a LOT faster than Windows when doing number crunching.
: > :
: > : Really? I have two "identical" CPUs running seti@home.
: >
: >
: > Do you really think some alien civilization is STUPID enough
: > to broadcast their presence when we are now using cable and
: > directional antennae for our own satellites?
: > It's "sets": search for extra terrestrial stupidity, and only the stupid
: > would participate.
: >
:
: But we haven't always done so. You're to quickly discounting (or
ignoring)
: the distance factor.
:
There are enough strange life-forms in our own oceans and rain forests to
keep
any biologist busy for a lifetime without looking for the exotic sci-fi
stuff.
You are too quickly assuming any extra terrestrial intelligence would be so
STUPID as to invite invasion by the bunch of war-like Neanderthals
we call "human" by broadcasting their existence to the universe, when we
have
broadcast our own war films showing just what we are really like and how
crazy we really are in destroying our own kind as well as other species.
If you want to find stupidity look no further than right here.