PC still playing Amiga catchup

[Karlos]

Yet there is still the sad fact that the latest PCs slow to a crawl when trying to multitask.

You are joking, right? There are hundreds of processes on my PC currently as well as several large applications.

There's also a CUDA simulation running which is pushing hundreds of megabytes of data per second across the PCI express bus and several mysql client processes interrogating a mysql server on the machine resulting in heavy disk IO.

The machine is still as responsive as when none of this was happening.

Just threw EUAE on top of the pile and it's running orders of magnitude faster than my actual amiga

[Karlos]

If that'd be the case there'd be a site called IBM.org where nutcases complaining about nowadays rigid systems, hard to upgrade and if there'd be any competion on the hardware market, technology would've been much more advanced. Don Estridge will be honoured as a god.
Plus there'd be someone who states you should NOT use any other computer than a mil. spec. AT 5170.

Probably. I dare say it's all happening in a parallel existence right now.

[Karlos]

@ Karlos

Just going from work experience.  Maybe "slow to a crawl" is a bad analogy.  If I'm scanning in anywhere from a few to several hundred pages, I can't do anything else on my system as its sending its data to the SQL server and processing the images.  You try and do anything, and the program crashes.  Probably just written poorly by the company who does our data system.  While it's working on processing, I just have to sit there and wait. It's really aggravating.

There could be any number of reasons for this. Bad application, dodgy drivers etc. However, if the machine is new, unless it's dirt cheap, it's unlikely to be down the the hardware.

[Karlos]

The Amiga as we all know and love it is long dead as a serious platform. CBM saw to that back in the early 90's.

There are literally dozens of operating systems out there, many of which will run on commodity PC hardware (which is the biggest hardware platform to target), are free and often a lot more mature than AmigaOS that are equally dead in the water as there's no real niche left for them. Between Windows, MacOS and Linux/U**x the OS market is totally sewn up.

[Karlos]

I doubt you have hundreds of processes running your PC.

No, you are quite right, there were only four at any given instant in time, one for each core*. However, a quick ps aux wwwf | less showed over 150 launched processes at the time I wrote that post.

*not including the 24576 GPU threads that were also active:

[Karlos]

Oh by the way, PCs do slow down to a crawl because so much viruses/spyware comes into the PC easily because no one knows exactly which file is meant for what and whether it's in its original state or tampered.

Right. Do you even understand the difference between a PC and PC running Windows?

[Karlos]

What is a BIP?

In the context of that display, "Billions of Interactions per Second", an "interaction" being the calculation of the change in velocity of a particle as a result of the gravitational force exerted on it and another particle.

The simulation is an all pairs n-body simulation. Each particle is simulated by a thread, all threads running concurrently (24576 being the maximum number of threads that can run on my GPU before it has to start switching between them).

[Karlos]

So, it's really a GIP...

Well, not really. I am reworking said example code into a charged particle simulation where each particle has a charge and mass. The force calculation then will be the Coulomb attraction between them. Unlike gravity, this force can be repulsive.

Also, the calculation is a bit more complex as I need one which has a maximum force potential at a distance equal to the sum of the radii of a pair of particles that becomes strongly repulsive at any distance less than that, regardless of the force potential (repulsive or attractive) at a distance greater than that.

I'm interested to see if such simulated charged particles of a given sets of mass, size and charge auto arrange in the way that ionic lattices do.

[Karlos]

The presence of GFLOP/s argues that BIP should be GIP (for consistency).

Is this one of your own coding projects?

The example image isn't, it's a code example provided with the CUDA devkit. The simulation I just described is, however. I'm using the n-body gravity simulation as a starting point.

[Karlos]

Cool.

GPU Gems article here (pdf)

[Karlos]

It means buttocks in Dutch, though....

That's good to know

[Karlos]

It obviously not that hardware. I kind doubt it just sort of bottle necks it self for 10 seconds every now and then. ;-)

The only time I've had total freezes on this machine is when I've done something really stupid, like attempting to launch 1,000,000 GPU threads simultaneously, just to see what happens. It completely maxed out the hardware.

X has locked up twice, both times due to a conflict between CUDA and Compiz. Easy to fix, ssh into the box and kill the X server.

The point is, the assertion in this thread that the "PC", as a platform  is playing catch up to the amiga is only true in the vivid imagination of a few Amiga fans that can't comprehend the difference between the PC and the OS that runs on it.

I have an A1, with an 800MHz G4, AGP Radeon 7000 gfx etc. It totally outclasses my classic A1200T in every way imaginable (except that the A1200 currently has more RAM installed ). However, aside from the CPU, it's made entirely out of standard "PC" hardware. And bloody old PC hardware at that.

My "PC", is about 1 year old and was fairly bleeding edge when I built it. In terms of hardware, it outclasses my A1 by an equally obscene amount. It's a hardware box. Windows doesn't come into it, since I run a 64-bit native linux as my main OS anyway.

However, Vista is installed on the machine and, as much as you'll all want to disagree, it flies like sh!t of a shovel. Which is just as well, since I only have it for gaming. You simply cannot play Crysis or Fallout 3 at 1680x1050 with all details turned up to maximum, having it run liquid smooth for several hours of solid gaming and then conclude "its slow and stops responding every now and then".

[Karlos]

Linux isn't as real-time as AmigaOS, though...
But LynxOS actually is.
I sure do want to try that baby B-)

Neither Linux or AmigaOS are realtime OS's and damn well you know it. Claiming one is more "realtime" than another is a bit misleading. A realtime kernel guarantees that an event requiring service will receive it within a specified time limit. No commonly used desktop OS makes this guarantee.

Clock for clock, interprocess communication under AmigaOS is faster than Linux, but considering that procersses run in completely separate memory spaces under linux, a zero copy messaging system isn't really feasible (shared memory segments aside), nor desirable from a memory protection perspective.

You can easily demonstrate where the argument falls over. Simply run a busy process on the AmigaOS at normal priority and see how responsive it isn't. Unless you install a better task scheduler (eg Executive), everything starts to crawl. You can even lock yourself out entirely if your busy process runs higher than priorirty 19 (input.device).

Under linux, I've been able to use machines where the load average was over 100.

[Karlos]

Hi,

@Karlos

I don't get it.

All I know is real time, and in real time my Amiga 4000 seems to get the job done faster than a Linux machine or a Windows machine.

That all depends on what the job is. My A1, for example would be dozens of times slower than my current linux box for the stuff I'm experimenting with at the moment and my classic machine many times slower again. My 040 manages say, what, 3.5 MFLOPS peak? Assuming I could write the necessary code in assembler to maintain that throughput (totally overlooking the complete lack of memory speed) that's about 101,000 times slower than my current PC manages. In reality it would be even slower given how slow the fsqrt instruction is (ie you'd never get the 3.5MFLOPS for these calculations).

By the time they get done booting up, my Amiga has usually completed the job and is ready for turning off. As for running processes, the Amiga usually starts to slow down after about several large processes. Still think it is a pretty good machine if you don't mind obsolete games with poor graphics.

Don't get me wrong, I love using my old miggies, but when it comes to work, it's all horses for courses.

Why aren't they bringing out games for the Amiga?

Not enough of a market, sadly.

By the way I like Linux to, I use Ubuntu for all my important stuff, I trust it more than crash and burn windows including XP.

smerf

Can't argue with that. I use ubuntu on my home PC, though work requires that I use fedora.

[Karlos]

Why not try it out on a REAL PC with standard hardware rather than specialized graphics cards.

First of all, it is a "real PC". The graphics card is no more out of place in this machine than any of the custom chips in my "real Amigas". This simulation runs on any PC that has a G80 or above based graphics card.

Secondly, there's nothing "specialised" whatsoever about the card. All current generation graphics cards tend to have fully programmable parallel arithmetic units.

Thirdly, I have run the same simulation entirely on the CPU. A naive single threaded implementation in the same "real PC" is about 250x slower than the GPU version on this machine. I can boost it significantly by optimizing it for four core execution and even further by using specific SSE3 vector operations. However, that naive version would still be 400x faster than my humble 040 could manage in a perfect world where memory bandwidth was infinite and all operations took one cycle. In the actual real world, it couldn't run it at all, there's not enough memory available to even hold the state information for this simulation.

Criticising the use of the GPU is also shooting your own argument for the Amiga in the foot. So far, you've extolled the virtue of using the custom chips for "realtime" performance, such as polling the joyport. If our experiment were simply filling flatshaded polygons on a 68000 amiga, would you be advocating the use of the CPU and not some "specialised graphics processor" ? Of course not.

Incidentally, do you really think a 2.6GHz CPU with 12MB of cache, even running the least optimized code in existence, isn't capable of polling a piece of hardware at 1kHz without missing a single iteration?