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The History, Status, and Future of FPGAs

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Re: The History, Status, and Future of FPGAs

#41

Post by tails4e »

d_silin wrote: post #9

I wonder if it is possible to add a (small) FPGA to a personal computer that could accelerate any specific software tasks (video/audio encoding, ML algorithms, compression, extra FPU capabilities) on user demand .

There absolutely is. There are PCIe cards you can plugin and use them as accelerators, just like you would use a GPU. Of course programming them to do the task you want is harder, but it can do anything. Saw a great example where someone implemented memcached on a single FPGA plugin and replaced many Xeons with it.

Re: The History, Status, and Future of FPGAs

#42

Post by mindentropy »

lnsru wrote: post #23

I am working right now on bare metal websockets implementation on Xilinx Series 7 FPGAs. Currently it’s ZynQ SoC, but final product will probably have Kintex 7 inside, so no Linux. The tools make me cry, no examples, application notes from 2014 with ancient libraries. I hope, vendors will fix tooling. But I see, Xilinx has released Vitis, so their scope is elsewhere, no interest in old crap. Using Git with Vivado is…

Have you looked at open source solutions? Tim Ansell is managing some great projects on open source solutions. Check out Symbiflow, LiteX, Yosys etc.

Re: The History, Status, and Future of FPGAs

#44

Post by exmadscientist »

tyingq wrote: post #34
jcranmer wrote: post #16

As a bit of a counterpoint: One of my prior projects involved working with a lot of ex-FPGA developers. This is obviously a rather biased group of people, but I saw a lot of feedback around that was very negative about FPGAs. One comment that's telling is that since the 90s, FPGAs were seen as the obvious "next big technology" for HPC market... and then Nvidia came out and pushed CUDA hard, and now GPGPUs have corner…

There is another traditional FPGA use case where you need real time data capture or signal generation. That seems to be getting eaten from the bottom now that there are really high speed MCUs that are easier to program. It's less efficient, but easier to develop for.

The other problem with using an FPGA here is that microcontrollers are cheap and have great cheap dev boards. FPGAs, not so much. I've wanted to just "drop in" a small FPGA in several designs, the way you can drop in a microcontroller, but there's no available FPGA that's not a massive headache in that use case. Trust me, I've looked.

The iCE40 series is almost there but not quite. It's a bit pricey (this is sometimes okay, sometimes a dealbreaker) but its care and feeding is too annoying. Who wants to source a separate configuration memory? Sometimes I don't have the space for that crap.

If any company can bring a small, cheap, low power FPGA to the market, preferably with onboard non-volatile configuration memory, a microcontroller-like peripheral mix (UART, I2C, SPI, etc.), easy configuration (re)loading, and with good tool and dev board support, they'll sell a lot of units. They don't even have to be fast!

Re: The History, Status, and Future of FPGAs

#45

Post by panpanna »

exmadscientist wrote: post #38
kyboren wrote: post #30

Earlier quoted context omitted.

GPUs work great for accelerating many applications, and it's true that that reduces interest in FPGAs. For applications that map well to GPUs, you're absolutely correct that the higher clock speeds (and greater effective logic area) make GPUs superior as accelerators. However, some applications do not map well to GPUs. Particularly those applications with a great deal of bit-level parallelism can achieve enormous spe…

Very much this. (Also, in general, FPGA tools are just some of the lowest quality garbage out there... and that is saying something. They're that bad . This is a completely unnecessary speedbump.) The rebuttal to your objection is always tools like "HLS" (High-Level Synthesis), or in English it's "C to HDL" (FPGAs are 'programmed' in the two Hardware Definition Languages VHDL (bad) or Verilog (worse, but manageable i…

> FPGA tools are just some of the lowest quality garbage out there

I think things are about to change thanks to yosys and other open source tools.

> VHDL (bad) or Verilog (worse,

VHDL (and its software counterpart Ada) are very well thought and great to use once you get to know them (and understand why they are the way they are). Yeah, they are a bit verbose but I prefer a strong base to syntactic sugar.

Re: The History, Status, and Future of FPGAs

#46

Post by iron2disulfide »

mindentropy wrote: post #40
TomVDB wrote: post #35

Earlier quoted context omitted.

Many years ago, we had a custom made board with 8 huge Xilinx Virtex 5 FPGAs (the largest available at the time) to emulate a large SOC. Those FPGAs were something like $20K a piece. We had 10 such boards, good for millions of dollars in hardware, and a small team to keep it running. These platform were mostly used by the firmware team to develop everything before real silicon came back. It could run the full design…

The multiple FPGA on a board is generally from Dini Group right? Fantastic boards. Ref: https://www.dinigroup.com/web/index.php

There are a lot of companies who create multi-FPGA boards. The market for FPGAs-for-ASIC-prototyping is substantial.

Re: The History, Status, and Future of FPGAs

#47

Post by panpanna »

exmadscientist wrote: post #44
tyingq wrote: post #34

Earlier quoted context omitted.

There is another traditional FPGA use case where you need real time data capture or signal generation. That seems to be getting eaten from the bottom now that there are really high speed MCUs that are easier to program. It's less efficient, but easier to develop for.

The other problem with using an FPGA here is that microcontrollers are cheap and have great cheap dev boards. FPGAs, not so much. I've wanted to just "drop in" a small FPGA in several designs, the way you can drop in a microcontroller, but there's no available FPGA that's not a massive headache in that use case. Trust me, I've looked. The iCE40 series is almost there but not quite. It's a bit pricey (this is sometime…

I think Cypress had a product line that combined a CPU and a small programmable array, just big enough to implement your own custom IO and protocols and maybe some minimal logic beyond that.

Maybe that's what most hobbyists need?

Re: The History, Status, and Future of FPGAs

#48

Post by kyboren »

exmadscientist wrote: post #38
kyboren wrote: post #30

Earlier quoted context omitted.

GPUs work great for accelerating many applications, and it's true that that reduces interest in FPGAs. For applications that map well to GPUs, you're absolutely correct that the higher clock speeds (and greater effective logic area) make GPUs superior as accelerators. However, some applications do not map well to GPUs. Particularly those applications with a great deal of bit-level parallelism can achieve enormous spe…

Very much this. (Also, in general, FPGA tools are just some of the lowest quality garbage out there... and that is saying something. They're that bad . This is a completely unnecessary speedbump.) The rebuttal to your objection is always tools like "HLS" (High-Level Synthesis), or in English it's "C to HDL" (FPGAs are 'programmed' in the two Hardware Definition Languages VHDL (bad) or Verilog (worse, but manageable i…

> The rebuttal to your objection is always tools like "HLS"

Yup. I know HLS has gotten a lot better recently but my impression is that, somewhat like fusion, HLS as a first-class design paradigm is always a decade away.

> FPGA tools are just some of the lowest quality garbage out there

Absolutely. I think the problem is vendors see FPGA tooling as a cost center and a necessary evil in order to use their real products, the chips themselves. Users are also highly technical and traditionally have no alternative, so (mostly) working but poor-quality software is simply pushed out the door. "They'll figure it out".

Finally, to expand on the difficulties imposed by physical constraints, I think another huge blocker to wide adoption is that FPGAs are physically incompatible. I cannot take a bitstream compiled for one FPGA and program it to any other FPGA. Hell, I can't even take a bitstream compiled for one FPGA and use that bitstream for any other device in the same device family. Without some kind of standardized portability, FPGAs will remain niche devices used only for very specific applications.

Re: The History, Status, and Future of FPGAs

#49

Post by jcranmer »

exmadscientist wrote: post #38
kyboren wrote: post #30

Earlier quoted context omitted.

GPUs work great for accelerating many applications, and it's true that that reduces interest in FPGAs. For applications that map well to GPUs, you're absolutely correct that the higher clock speeds (and greater effective logic area) make GPUs superior as accelerators. However, some applications do not map well to GPUs. Particularly those applications with a great deal of bit-level parallelism can achieve enormous spe…

Very much this. (Also, in general, FPGA tools are just some of the lowest quality garbage out there... and that is saying something. They're that bad . This is a completely unnecessary speedbump.) The rebuttal to your objection is always tools like "HLS" (High-Level Synthesis), or in English it's "C to HDL" (FPGAs are 'programmed' in the two Hardware Definition Languages VHDL (bad) or Verilog (worse, but manageable i…

Again, a counterpoint:

I worked on hardware for something akin to a FPGA on a much coarser granularity (kind of like coarse-grained reconfigurable arrays)--close enough that you have to adapt tools like place-and-route to compile to the hardware. The programming for this was mostly driven in pretty vanilla C++, with some extra intrinsics thrown in. This C++ was close enough to handcoded performance that many people didn't even bother trying to tune their applications by resorting to hand-coding in the assembly-ish syntax.

This helped bolster my opinion that FPGAs aren't really the answer that most people are looking for, and that there are useful nearby technologies that can leverage the benefits of FPGAs while having programming models that are on par with (say) GPGPU.

Re: The History, Status, and Future of FPGAs

#50

Post by TomVDB »

mindentropy wrote: post #40
TomVDB wrote: post #35

Earlier quoted context omitted.

Many years ago, we had a custom made board with 8 huge Xilinx Virtex 5 FPGAs (the largest available at the time) to emulate a large SOC. Those FPGAs were something like $20K a piece. We had 10 such boards, good for millions of dollars in hardware, and a small team to keep it running. These platform were mostly used by the firmware team to develop everything before real silicon came back. It could run the full design…

The multiple FPGA on a board is generally from Dini Group right? Fantastic boards. Ref: https://www.dinigroup.com/web/index.php

No, it was in-house custom made for the purpose.

Huge PCBs, ~2ft by 2ft.

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