Mail Archives: pgcc/1998/07/23/05:13:49
Hello!
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>>>is horribly outdated.
>>
>>gcc is still supporting 80386, ns32000 (I did work on such a beast
>>in 1989), m88k, pdp11 and some other old architectures.
>>
>>I still think that you are comparing different things and argue in a
>>wrong way.
>>
>>First of all, it is *OUR* (mostly Marc's) decision which CPU's he likes
>>to support. This is a loosely connection of some people who spare their
>>free time to improve performance on whatever CPU's they like. In most
>>cases these are the CPU's the own or have access to. So if you *REALLY*
>>want them to boost the performance of some special design, then you
>>should not flame them, you rather should look for a way to give them
>>partial/full access to such a machine. Since this is not a commercial
>>company, do not expect that everyone of us has a rich grandmother or some
>>other sponsor with never ending money. This is the reason why the cheaper
>>(the CHEAPER not the slower) CPU's are better supported.
>>
>>Then there are patents on Intels PII-Bus, even memory cycles are patented
>>(look at cyrix).
>>
>>>>What about selling your program bundled with a quattro-Xeon-board ;-)
>>
>>Look at the smile, this was ment as a joke.
>>
>>>I'm sure next Worldchampionship a lot will run on XEON or faster
>>>(previous world championship, octobre 1997 a lot ran on Alpha,
>>>two participants even ran at an experimental alpha 767Mhz!).
>>>
>>>I can't afford such computers, therefore i make my program parallel.
>>
>>I do not have a problem with someone running his programs on alpha's or
>>HAL's or whatever, as long as they do not flame people, which spend their
>>free time for fun and not for money in projects *they* decide.
>>
>>>A dual board is something like 300US dollar, a PII-333 chip will be around
>>>250US within a few months, so i have 666Mhz then for a horrible cheap
>price,
>>... and will then be outdated too ...
>>
>>>which might equal a 500Mhz XEON (i estimate that i lose around
>>>10% because of parallellism so i'm having a PII-600Mhz in fact when
>>>compared to single CPU).
>>
>>The loss of speed could be bigger when you have a lot of concurrent
>>memory accesses, but you have to prove that.
>>
>>>When the all categories world champs chesscomputer are held this quattro
>xeon
>>>system will be not by far the fastest system. We can expect 1 cray entry,
>>>a 32 processor sun/sparc, a 40 processor system (about speed of 200Mhz,
>>>a 32 processor PII-300 system, and at least 1 4 processor system.
>>
>>What about a program which runs on 5 200Mhz - AMD's connected by 100-Mbit
>>ethernet? Chess is one of these programs which can perfectly run parallel.
>>Did you compare the costs of 5 motherbords with outdated socket-7 cpus with
>>the cost of 1 high-performance-up-to-date two-processor board? I think this
>>will be equal in price, but the performance could be much better.
>First of all they will be slower (slow processor and not having
Maybe slow processor for your special problem, but fast enough for mine.
>shared memory), secondly it's cheaper to buy
>a PII-400 dual within a few months
In the last posting you wrote PII-333. Don't forget that *ALL* cpu's will
be cheaper then, so avoid to compare today's price of of one with tomorrow's
price of the other.
>and carry that with you, than taking with you
>5 computers + keyboards + all power + 100-Mbit ethernet cards + seperate
>memory.
Some boards do not need keyboards and monitors, Linux does not need this
stuff to boot.
>100-Mbit ethernet cards protocol is btw rather slow compared to
>shared memory.
True, but
>As you probably don't know: at intel processor there is a special
>instruction to lock on atom-level.
If your lookahead of moves decides to choose one, than everything from that
time until the final decision is intependent from each other. Therefore
I do not see so much need of the LOCK-prefixes.
BTW: This is assembler and not C.
>Locking and stuff using ethernet cards will require considerable more time.
>>>I might be forgetting some others running on multi-processor alpha's,
>>>and optionally a french multiprocessor program might enter too at a
>>>cray.
>>Don't forget Deep Thought (is this the right name?) which was especially
>>designed by IBM some years ago.
>that were hardware chips connected to a fast mainframe/supercomputer.
>Not the general purpose processor did the big job, but the processors.
>Not smart to use examples you don't know what it did.
>>>Although all of these systems are out of your reach, for others it's not.
>>
>>Oops! Why do you know that these systems are not in my reach? I do not want
>>to buy always the fastest, the newest, the best, the whatever. I do not
>>buy computers to show them my neighbours. I just do not want to spend so
>>much money in things which get outdated so fast.
>>But I agree, brute force is needed for your problem, maybe you can give
>>Marc (or someone else) access to such a machine and you will sure see a
>>better performance soon, but please argue in a more constructive way.
>If you don't care for getting a fast machine then why do you want
>to optimize code on it?
>I mean: if you still now put all your spare time in making optimizations
>for AMD K6 instead of PII/PRO, then your time will be wasted;
It is still my time and I decide how to waste it. I would not even think
of telling you, that you waste your time with chess. You like it, so it
is ok. Pgcc is optimizing some chips better and others not. This is ok
too.
>at the time a new pgcc version which can achieve reasonably optimization
>is ready everyone will be able to buy PII cpu's, like you can buy now AMD K6.
When everyone can buy some, then some of these will help optimizing the
compiler and then it will get faster. No one in the world is running in
god-mode, so no one has the right to tell me what computer I should buy.
It is my money, it is my time, therefore I decide.
>Look how weird gcc is right now.
>It can optimize EXCELLENT for 486 processors, but it works horrible on PII
>chips.
No! Maybe for your problem there is not enough optimization, but for others
it is enough.
>Even you don't have a 486 processor anymore. For a low budget you get a
>K6 now.
>>>>>Vincent
>>>>--
>>>>Wolfgang Formann
>>--
>>Wolfgang Formann
--
Wolfgang Formann
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