特斯拉双精度
我正在寻找有关 tesla gpu 中硬件如何实现双精度的信息。我读过,两个流处理器正在处理单个双精度值,但我没有找到 nvidia 的任何官方论文。
提前致谢。 聚苯硫醚 为什么大多数 GPU 仅以单精度进行计算(因为颜色可以存储为 RR.GG.BB.TT,其中每个字符都是 8 位值)?
聚苯乙烯 帮我用谷歌搜索没有帮助
I am looking for the information, how double precision is hardware implemented in the tesla gpu . I have read, that two stream processors are working on the single double value, but i didn't found any official paper from nvidia.
Thanks in advance.
PPS
Why most GPU are computing with only single precision (because colors can be stored as RR.GG.BB.TT, where each character is a 8-Bit value)?
PS
google it for me didn't help
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不支持双精度并不是像您所说的存储格式问题(RR.GG.BB.TT),而是具有用于处理双精度操作(add、mul、madd 等)的本机内在函数(以及专用硬件)。
不管怎样,大多数GPU只支持单精度,因为GPU市场大部分是在游戏市场,而游戏玩家不需要双精度。此外,大多数游戏玩家都在寻求良好的性价比。就晶体管预算(和 TDP)而言,实现 DP 的成本很高,如果游戏不使用双精度,则毫无意义。
这就是为什么您会看到高端 ATI GPU 支持双核(HD 59xx 和 HD 58xx,但不支持 HD 57xx 等中级和入门级 GPU)。
@卡尔菲利普:
是的,你是对的,IEEE754(有点)适用于 GTX 260 等 GPU,但当前的 ATI 和 NVIDIA 一代支持 高端部件上的 IEEE 754-2008。
关于硬件实现,这是 IHV 通常不会透露的秘密:)
Not supporting double is not a matter of storage format like you said (RR.GG.BB.TT) but having native intrinsics (and so dedicated hardware) for handling operations on double (add, mul, madd, etc).
Anyway, most GPU supports only single precision because where most of the GPU market lies is in the gaming market and gamers don't need double precision. Also most of gamers are looking for good performance/price ratios. Implementing DP is costful in term of transistor budget (and TDP), and if games don't use double precision this is meaningless.
This is why you see high-end ATI GPUs supporting double (HD 59xx and HD 58xx, but not mid and entry-level GPUs such as HD 57xx and less).
@karlphillip:
Yes you're right, IEEE754 (kind of) for GPUs like GTX 260, but current ATI and NVIDIA generation is supporting IEEE 754-2008 on high-end parts.
About hardware implementation, this are secrets IHVs usually don't tell :)
Tesla 不是 GPU,而是一系列具有各种高端 GPU 的协处理器。如果你的 Tesla 内部有 Fermi GPU,它应该具有良好的双精度性能。
请参阅 Fermi 白皮书,第 9 页。
单精度更重要用于常规 GPU 计算,因为它足以满足此类应用程序的需要。
Tesla is not a GPU, it's a line of coprocessors featuring various high-end GPUs. If your Tesla has a Fermi GPU inside, it should have good double precision performance.
See the Fermi white paper, page 9.
Single precision is more important for regular GPU computing because it is sufficient for such applications.
根据 Wiki:
对于双精度(仅在 GTX 260 等较新的 GPU 中支持) 12])与 IEEE 754 标准存在一些偏差:舍入到最近偶数是倒数、除法和平方根唯一支持的舍入模式。在单精度中,不支持非正规值和信号 NaN;仅支持两种 IEEE 舍入模式(斩波和舍入到最接近的偶数),并且这些模式是在每条指令的基础上指定的,而不是在控制字中指定的;除法/平方根的精度略低于单精度。
就是这样,它们实现了 IEEE 754,但实际的实现可能是私有的和秘密的。
According to Wiki:
For double precision (only supported in newer GPUs like GTX 260[12]) there are some deviations from the IEEE 754 standard: round-to-nearest-even is the only supported rounding mode for reciprocal, division, and square root. In single precision, denormals and signalling NaNs are not supported; only two IEEE rounding modes are supported (chop and round-to-nearest even), and those are specified on a per-instruction basis rather than in a control word; and the precision of division/square root is slightly lower than single precision.
There you go, they implement most of the spec of IEEE 754, but the actual implementation is probably private and secret.