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There was an article at Ars [1] that explained how Microsoft uses FPGA powered network cards at Azure. The idea is to move "network decision making" (load bala
by airesQ 10y ago
There was an article at Ars [1] that explained how Microsoft uses FPGA powered network cards at Azure.
The idea is to move "network decision making" (load balancing; maybe firewalls and other assorted stuff) from the CPU to the FPGA, where this kind of thing can be done faster, and more reliably (e.g. you can have hard timing constraints on a FPGA).
Guess the other players in this field are pure software switches, which can be very flexible, but sometimes slow. And ASICs, which are very fast (potentially faster than FPGAs) but not as flexible.
[1] - http://arstechnica.co.uk/information-technology/2016/09/microsoft-azure-fpga-supercomputer-details/ http://arstechnica.co.uk/information-technology/2016/09/micr...
- derefr 10y agoI always thought the "best-practice" architecture for these sort of high-speed SDN switches was to have a custom ASIC "data plane" (hard realtime) that can be signalled from a CPU "control plane" (running something soft realtime like Erlang.) Would an FPGA really give advantages over such a setup? I can't imagine it'd beat the CPU at being a control plane—so it'd mostly have to be that it has a lower TCO as a data plane than an ASIC. That might be true, if the code in the data-plane would ever need updates (which, for ASICs, mean new hardware revs.)
- nickpsecurity 10y agoYeah, it would have an advantage: you could deploy it without spending hundreds of thousands of dollars on ASIC production or prototyping. It's the main use for FPGA's. They're better so long as unit price is cheaper than masks and such for ASIC's. In this case, each customer would have a relatively small number of the switches where volume doesn't justify an ASIC. Might be enough switches & customers to justify licensing a FPGA core with development cost spread out among many customers.
- vvanders 10y agoAlternatively you can also re-configure the FPGA for specific loads where ASIC is always fixed. Downside is of course lower speed and higher power consumption.
- nickpsecurity 10y agoI shouldve mentioned that. Tks for catch. Reconfiguration is huge selling poinf for them. Gone from HTTP 1 to 1.1 or 2.0? Just upload the new bitstream. Got a better algorithm or bug fix? Upload new bitstream. ASIC folks be like, "You gonna neef to bring a soldering iron for that update. Or buy our latest model." Haha.
- wmf 10y agoAt Azure scale, ASICs would definitely be cheaper but they're still using FPGAs for the flexibility. OTOH AWS is using ASICs so we can see that different clouds have made different tradeoffs.
- nickpsecurity 10y agoProbably. Azure scale is a rare example, though. Most of the time a company will be much lower volume. They might consider S-ASIC's like at eASIC before ASIC's. Prototyping cost at eASIC can be as cheap as $50,000 per some writeups thanks to the eBeam machine. With low costs, they're easier to swap out than full on ASIC's too.