7 ms·

Then you can increase the power consumption of all electronics by 50+% and halve the processing power. And that is optimistic.

vanderZwan 9y ago
Sincere question: how much of that is inherent to FPGA systems, and how much of that is due to them being a niche technology used in contexts where there power consumption is not a big issue, meaning that there has not been a significant drive to reduce power consumption? I mean, it's not like the other types of electronics are inherently energy-efficient either: before it affected battery life people didn't care that much about energy-efficient CPU's. The current drive for more computation per Watt is largely driven by the explosion in mobile hardware.
- kec 9y ago
  It's inherent to how FPGAs work. Logic blocks are necessary but are kind of a heavyweight solution to emulate normal logic (and they'll result in a ton of extra silicon driving leakage up). Perf/Watt has always been interesting as well, It's a major concern for data centers (worse perf/Watt requires more cooling which drives costs up).
tombert 9y ago
Yeah, hence my "laws of physics" thing at the end. I am just saying that it would be interesting if that was something reasonable to do.
awelkie 9y ago
I appreciate what you're saying, but for devices with long lifetimes things may not be so clear. Consider a wifi device with a >15 year lifetime. Let's say such a device was built with SDR and FPGA, it conformed to 802.11b, and it used twice the power of an equivalent ASIC design. But 15 years later, this device was able to upgrade in software to 802.11ac, and so it was able to take advantage of spatial multiplexing and higher-order modulation to lower its power usage. So now this device uses twice as much power as an equivalent 802.11ac ASIC, but maybe it's more power efficient than that 802.11b ASIC from 15 years earlier. I guess what I'm saying is that by allowing a device to upgrade in software to more power-efficient designs, you might claw back some of the efficiency lost by using an FPGA when you consider the entire product's lifetime.
- vanderZwan 9y ago
  Even if all of this works, there is still another issue: a potential rebound effect. If mobile phone software has taught us anything, it is that when updates become cheap, we start getting goodness-knows-how-many patches every other month or even week. How much bandwidth is wasted on redownloading app "updates" every week that represent a few lines of code change? ... huh, I wonder is that is what happened with DNA and those jumping genes.
- RandomOpinion 9y ago
  > I guess what I'm saying is that by allowing a device to upgrade in software to more power-efficient designs, you might claw back some of the efficiency lost by using an FPGA when you consider the entire product's lifetime. That presumes you put in a big enough FPGA/CPU or whatever fifteen(!) years in advance that has enough resources to handle the increased processing requirements for a future protocol (expensive and wasteful and there's no guarantee that you didn't guess wrong and it's still too small/slow) and that your RF signal path was designed well enough to handle the new signal requirements (expensive and wasteful even if you were prescient enough to guess what future requirements were). And that's on top of the fact that inexpensive electronic devices simply aren't built with components rated to last 15 years. tl;dr software doesn't change the laws of physics

vanderZwan 9y ago

Sincere question: how much of that is inherent to FPGA systems, and how much of that is due to them being a niche technology used in contexts where there power consumption is not a big issue, meaning that there has not been a significant drive to reduce power consumption? I mean, it's not like the other types of electronics are inherently energy-efficient either: before it affected battery life people didn't care that much about energy-efficient CPU's. The current drive for more computation per Watt is largely driven by the explosion in mobile hardware.

kec 9y ago
It's inherent to how FPGAs work. Logic blocks are necessary but are kind of a heavyweight solution to emulate normal logic (and they'll result in a ton of extra silicon driving leakage up). Perf/Watt has always been interesting as well, It's a major concern for data centers (worse perf/Watt requires more cooling which drives costs up).

tombert 9y ago

Yeah, hence my "laws of physics" thing at the end. I am just saying that it would be interesting if that was something reasonable to do.

awelkie 9y ago

I appreciate what you're saying, but for devices with long lifetimes things may not be so clear. Consider a wifi device with a >15 year lifetime. Let's say such a device was built with SDR and FPGA, it conformed to 802.11b, and it used twice the power of an equivalent ASIC design. But 15 years later, this device was able to upgrade in software to 802.11ac, and so it was able to take advantage of spatial multiplexing and higher-order modulation to lower its power usage. So now this device uses twice as much power as an equivalent 802.11ac ASIC, but maybe it's more power efficient than that 802.11b ASIC from 15 years earlier. I guess what I'm saying is that by allowing a device to upgrade in software to more power-efficient designs, you might claw back some of the efficiency lost by using an FPGA when you consider the entire product's lifetime.

vanderZwan 9y ago
Even if all of this works, there is still another issue: a potential rebound effect. If mobile phone software has taught us anything, it is that when updates become cheap, we start getting goodness-knows-how-many patches every other month or even week. How much bandwidth is wasted on redownloading app "updates" every week that represent a few lines of code change? ... huh, I wonder is that is what happened with DNA and those jumping genes.
RandomOpinion 9y ago
> I guess what I'm saying is that by allowing a device to upgrade in software to more power-efficient designs, you might claw back some of the efficiency lost by using an FPGA when you consider the entire product's lifetime. That presumes you put in a big enough FPGA/CPU or whatever fifteen(!) years in advance that has enough resources to handle the increased processing requirements for a future protocol (expensive and wasteful and there's no guarantee that you didn't guess wrong and it's still too small/slow) and that your RF signal path was designed well enough to handle the new signal requirements (expensive and wasteful even if you were prescient enough to guess what future requirements were). And that's on top of the fact that inexpensive electronic devices simply aren't built with components rated to last 15 years. tl;dr software doesn't change the laws of physics