3 ms·
This write up seems to only refer to on fpga ram which is fast, but very limited. In fact the author seems to completely ignore using any ram external to the fp
by le-mark 3y ago
This write up seems to only refer to on fpga ram which is fast, but very limited. In fact the author seems to completely ignore using any ram external to the fpga. Certainly fpga have capacity to interface with DDR ram of various types, and the more expensive fpga the better, but that also impacts the performance quiet a lot, making performance more in line with a normal non specialized device; beacause memory access time dominates.
- pjc50 3y ago> making performance more in line with a normal non specialized device; because memory access time dominates. Well, yes. With a short enough piece of network cable it's probably lower latency to query a different one of these devices a short way away than wait for DRAM to very slowly charge up a row.
- adam_walker 3y agoYes, this is about building a small hashtable in the RAMs internal to the FPGA. As you pointed out, things would slow down a bit if you had to go to external RAM. However, if you are building a hashtable in external RAM that is accessed via Ethernet, I think there are still some performance gains to be had with an FPGA compared to a non-specialized device. For one, you get to skip the PCIe bus with an FPGA, reducing latency, since the Ethernet transceivers go straight into the FPGA fabric. Also, while I don't know a lot about power consumption, I expect it would be a fair bit lower on a dedicated FPGA compared to a server performing the same work.