top | item 24527126

(no title)

gj_78 | 5 years ago

I really do not understand why a (very good) hardware provider is willing to create/direct/hint custom software for the users.

Isn't this exactly what a GPU firmware is expected to do ? Why do they need to run software in the same memory space as my mail reader ?

discuss

order

blelbach|5 years ago

NVIDIA employs more software engineers than hardware engineers.

> Why do they need to run software in the same memory space as my mail reader ?

It is a lot more expensive to build functionality and fix bugs in silicon than it is to do those same things in software.

At NVIDIA, we do as much as we possible can in software. If a problem or bug can be solved in software instead of hardware, we prefer the software solution, because it has much lower cost and shorter lead times.

Solving a problem in hardware takes 2-4 years minimum, massive validation efforts, and has huge physical material costs and limitations. After it's shipped, we can't "patch" the hardware. Solving a problem in software can sometimes be done by one engineer in a single day. If we make a mistake in software, we can easy deploy a fix.

At NVIDIA we have a status for hardware bugs called "Won't Fix, Fix in Next Chip". This means "yes, there's a problem, but the earliest we can fix it is 2-4 years from now, regardless of how serious it is".

Can you imagine if we had to solve all problems that way? Wait 2-4 years?

On its own, our hardware is not a complete product. You would be unable to use it. It has too many bugs, it doesn't have all of the features, etc. The hardware is nothing without the software, and vice versa.

We do not make hardware. We make platforms, which are a combination of hardware and software. We have a tighter coupling between hardware and software than many other processor manufacturers, which is beneficial for us, because it means we can solve problems in software that other vendors would have to solve in hardware.

> I really do not understand why a (very good) hardware provider is willing to create/direct/hint custom software for the users.

Because we sell software. Our hardware wouldn't do anything for you without the software. If we tried to put everything we do in software into hardware, the die would be the size of your laptop and cost a million dollars each.

You wouldn't buy our hardware if we didn't give you the software that was necessary to use it.

> Isn't this exactly what a GPU firmware is expected to do ?

Firmware is a component of software, but usually has constraints that are much more similar to hardware, e.g. long lead times. In some cases the firmware is "burned in" and can't be changed after release, and then it's very much like hardware.

Const-me|5 years ago

> Isn't this exactly what a GPU firmware is expected to do?

The source data needs to appear on the GPU somehow. Similarly, the results computed on GPU are often needed for CPU-running code.

GPUs don’t run an OS and are limited. They can’t possibly access file system, and many useful algorithms (like PNG image codec) is a poor fit for them. Technically I think they can access source data directly from system memory, but doing that is inefficient in practice, because GPUs have a special piece of hardware (called copy command queue in d3d12, or transfer queue in Vulcan) to move large blocks of data over PCIe.

That library implements an easier way to integrate CPU and GPU pieces of the program.

dahart|5 years ago

What do you mean about running in the same memory space? Your operating system doesn’t allow that. Is your concern about using host memory? This open source library doesn’t automatically use host memory, users of the library can write code that uses host memory, if they choose to.

How would a firmware help me write heterogeneous bits of c++ code that can run on either cpu or gpu?

blelbach|5 years ago

> What do you mean about running in the same memory space? Your operating system doesn’t allow that. Is your concern about using host memory?

Actually, the basis of our modern GPU compute platform is a technology called Unified Memory, which allows the host and device processor to share access to memory spaces. We think this is the way going forward.

Of course, there's still the process isolation provided by your operating system.

gj_78|5 years ago

IMHO, the question is not that we need code to run on CPUs and GPUs , we do need that, The question is whether the GPU seller has to control both sides. Until I buy a CPU from nvidia I want to keep some kind of independence.

When will we be able to use a future riscv-64 CPU with an nvidia GPU ? we will let the answer to nvidia ?