Einstein@home 以后有可能支持 CUDA~

Youth

有人问到eah有没有考虑支持一下最近挺热门的gpu计算，然后Bernd老大回了篇：


http://einstein.phys.uwm.edu//fo ... p;nowrap=true#84907

I got some code from a masters student who worked on porting the FStat engine to CUDA. Looks like a factor of 7 speedup, but he's still struggling with the few calculations in there that require double precision. There might be an App some time during S5R4.

我从一位研究生那拿到一些代码，他做了些工作，把FStat引擎移植到CUDA，看上去大概有7倍的速度提升，但有些需要双精度的计算还没搞定，等我们项目进行到S5R4阶段的时候，可能会有GPU版的计算程序吧。


然后有人建议，如果双精度计算是必须的，可以把GPU限制在G200系列...

DrLingCN

不能限定在G200系列啊！
一定要所有支持CUDA的卡都支持计算！

sakeki

限定G200可以，但起码得推迟一年才有足够用户。

Mr.Cancel

速度有7倍的提升啊，很诱人哦！

zglloo

看来E@H 也要向GPU靠拢    那么SETI WCG  R@H早应该  也来这几个项目 也应该可以 移植把！

Youth

估计还是看适合不适合吧。

昨天翻boinc官方的文档似乎是已经支持项目方使用gpu的计算程序（服务端和客户端应该都得用6系才行），但也提到一个问题，似乎没有办法知道其它程序是否在使用gpu（How does BOINC know if non-BOINC applications are using resources? ）。

Bismarck

如果能把GPU的流处理器都分组并赋予不同的工作，那还是可以的

refla

那ATI的1000、2000、3000系列咋样？

Youth

cuda也好，ati的卡也好，对eah来说应该都还早吧，遥远地期待一下就好了：）

refla

嗯，有道理。特别是不支持双精度类型，对于科学计算那可是致命伤。

Youth

Posted 23 Jun 2008 13:36:08 UTC

There are rather few of them. Right now I'm not sure that supporting GPU is worth the effort at all. Anyway, I'm pretty sure that the remaining issues can be resolved by emulating the double precision e.g. with two floats or a float and an int. But first you'll have to find out what precisely goes wrong, and that's where we're stuck atm.

应该是需要双精度计算的地方并不多，目前还不确定支持GPU是否有必要，但我确信剩下的问题应该可以通过用两个单精度浮点数或一个单精度浮点数加一个整数来模拟双精度计算来解决，但首先还是必须搞清楚问题倒底在哪。

Youth

Posted 25 Jun 2008 18:30:19 UTC

There is no standard for GPU computing (yet). Picking one particular model: how many Einstein@home participants do have an NVidia Quadro card that they want to actually use for crunching? Remember that displaying anything is not (yet) possible when using the GPU for numerical calculations.

GPU计算还没有一个标准。会有多少EAH的用户拥有Quadro显卡并且愿意拿来计算呢？要记住使用GPU进行数据计算的时候是不能显示任何东西的（直译，意思应该是说计算时给显卡带来的负担比较重吧）。

As far as I understand the Folding@home application is based on Brook or some similar higher level language, the Einstein@home application is (currently) not. Our "Fstat engine" could be thought of as an FFT for narrow frequency bands. It's actually possible to use standard FFT implementations to calculate it, but in the current framework this would be rather inefficient. The current code was chosen for Einstein@home because it allows us to split the frequency bands into many small pieces (workunits), keeping computing time and data transfer volume within the bounds of a volunteer computing project.

就我（Bernd）理解，FAH的程序是基于Brook或类似的高级语言，EAH目前还不是。我们的Fstat引擎可以认为是窄频段的FFT（快速傅立叶转换）。使用标准FFT也是可以的，但在目前的框架下将会效率不高。EAH选择当前的代码是因为它允许我们把频段分为很多小块（任务包），使任务包的计算时间或数据传输时间在志愿计算项目能允许的范围内。

Pinkesh Patel (a LSC member) is working on a program that actually uses standard FFT algorithms (I think with little modifications) for calculating the F-Statistic, but his code isn't ready to be used yet (at least not on E@H), using it would require a completely different search- and workunit design, and it would be much more demanding for machines and their connection to the servers than what we currently expect our participants to have.

LSC的一位成员正在写一个利用标准FFT算法（我认为会有些小改动）的程序来计算F-Statistic，但是他的代码还没准备好使用（至少对于EAH），使用它将需要对项目进行完全不同的搜寻和任务包设计，并且将对用户的计算设备和网络连接带来高得多的要求。

I definitely think that using high-level languages / libraries like Brook that have efficient implementations for every platform is the way to go in the future, but for the moment (i.e. S5R4) we need to stick to what we have.

我非常确信使用Brook之类的在各个平台都能有不错效率的高级语言或语言库是大势所趋，但就目前来说（比如S5R4），我们还得像之前一样。


// 看来S5R4能出GPU版的希望基本破灭了...

BiscuiT

在DX11出来之前只能用 FAH 安慰gpu的分布式计算。。

Youth

Posted 26 Jun 2008 11:50:34 UTC

I understand that even for Folding@Home, the workunits crunched by the GPU beta clients are different from those for the other platforms. But they did manage to do visualization and GPU processing at the same time now, so that you can still use your PC's video capabilities while crunching, which should improve acceptance.

That's quite amazing. I've been told that this is impossible.

Actually running a second Application (and Workunits) on the same project is quite possible on BOINC, though I don't know how many projects actually do this (I could imagine Leiden Classical). Erik Korpela is visiting the AEI this week, he told us that SETI@home will run Astropulse as a second Application some time soon. We're currently looking into implementing it, it might become an option for Einstein@home, too. This way we could actually run a "stream computing" search in parallel.

看来前面那句直译的没问题。。。

Bikeman提示说FAH那边在计算时是还可以显示图形的，另外就是，FAH那边GPU的客户端也和普通的客户端不同。

BM说他也已经听说了，说是也可以考虑项目中同时使用两个计算程序。

zglloo

DirectX 11当中，解决GPU内部浮点渲染精度不统一的问题，达成32bit浮点渲染精度，为不同厂商GPU使用相同的通用计算驱动程序和API  D11到底是否能达到如期效果还是需要怀疑下