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I want a good parallel computer

raphlinus.github.io

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Re: I want a good parallel computer

#201

Post by deviantbit »

Diggsey wrote: post #136
deviantbit wrote: post #49

"I believe there are two main things holding it back." He really science’d the heck out of that one. I’m getting tired of seeing opinions dressed up as insight—especially when they’re this detached from how real systems actually work. I worked on the Cell processor and I can tell you it was a nightmare. It demanded an unrealistic amount of micromanagement and gave developers rope to hang themselves with. There’s a re…

> I worked on the Cell processor and I can tell you it was a nightmare. It demanded an unrealistic amount of micromanagement and gave developers rope to hang themselves with. So the designers of the Cell processor made some mistakes and therefore the entire concept is bunk? Because you've seen a concept done badly, you can't imagine it done well? To be clear, I'm not criticising those designers, they probably did a g…

[flagged]

Re: I want a good parallel computer

#203

Post by __tidu »

PicassoCTs wrote: post #133
monocasa wrote: post #91

Earlier quoted context omitted.

It does. GPUs have full MMUs.

They do? Then how do i do the forbidden stuff by accessing neighboring pixel data?

do you mean accessing data outside of your app's framebuffer? or just accessing neighboring pixels during a shader pass, because those are _very_ different things. GPU MMUs mean that you cant access a buffer that doesn't belong to your app that's it, its not about restricting pixel access within your own buffers

Re: I want a good parallel computer

#204

Post by zozbot234 »

0xbadcafebee wrote: post #194
zozbot234 wrote: post #86

Earlier quoted context omitted.

SSI is an interesting idea, but the actual advantage is mostly to improve efficiency when running your distributed code on a single , or few nodes. You still have to write your code with some very real awareness of the relevant issues when running on many nodes, but now you are also free to "scale down" and be highly efficient on a single node, since your code is still "natively" written for running on that kind of s…

You could say the same thing about multiple cores or CPUs. A lot of people write apps that aren't useful past a single core or CPU. Doesn't mean we don't build OSes & hardware for multiple cores... (Remember back when nobody had an SMP kernel, because, hey, who the hell's writing their apps for more than one CPU?! Our desktops aren't big iron!) In the worst-case, your code is just running on the CPU you already have.…

> It might take a miracle for the code to get adopted upstream by the Linux Mafia, though

The basic building block is containerization/namespacing, which has been adopted upstream. If your app is properly containerized, you can use the CRIU featureset (which is also upstream) to checkpoint it and migrate it to another node.

Re: I want a good parallel computer

#205

Post by PicassoCTs »

__tidu wrote: post #203
PicassoCTs wrote: post #133

Earlier quoted context omitted.

They do? Then how do i do the forbidden stuff by accessing neighboring pixel data?

do you mean accessing data outside of your app's framebuffer? or just accessing neighboring pixels during a shader pass, because those are _very_ different things. GPU MMUs mean that you cant access a buffer that doesn't belong to your app that's it, its not about restricting pixel access within your own buffers

TIL. Thank you.

Re: I want a good parallel computer

#206

Post by Wumpnot »

I had hoped the GPU API would go away, and the entire thing would become fully programmable, but so far we just keep using these shitty APIs and horrible shader languages.

Personally I would like to use the same language I write the application in to write the rendering code(C++). Preferably with shared memory, not some separate memory system that takes forever to transfer anything too. Somelike along the lines of the new AMD 360 Max chips, but graphics written in explicit C++.

Re: I want a good parallel computer

#207

Post by musicale »

deviantbit wrote: post #49

"I believe there are two main things holding it back." He really science’d the heck out of that one. I’m getting tired of seeing opinions dressed up as insight—especially when they’re this detached from how real systems actually work. I worked on the Cell processor and I can tell you it was a nightmare. It demanded an unrealistic amount of micromanagement and gave developers rope to hang themselves with. There’s a re…

> I really believe I need to spend 2-weeks requiring students write code on an Amiga, and the programs have to run at the same time. If anyone of them crashes, they all will fail my course.

Fortran is memory-safe, right? ;-)

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