5 ms·
How much does TCP offload help in practice, in particular for TLS connections? Is it a 20% improvement, a 2X improvement, etc.? That would be good to know to ev
by telotortium 7y ago
How much does TCP offload help in practice, in particular for TLS connections? Is it a 20% improvement, a 2X improvement, etc.? That would be good to know to evaluate the performance of QUIC in the article.
- unethical_ban 7y agoI don't understand how TLS makes a difference. They are different layers of the stack.
- gok 7y agoI think the question is: given that you're going to be performing pretty heavy symmetric encryption on every byte anyway, how much can TCP offload really help when all it's handling is the relatively trivial checksum and sliding window computation?
- geocar 7y agoHaving 40Gb/sec TCP is great but if you can't come up with 40Gb/sec to put into it, "what's the point?" Of course, you could just buy a TLS accelerator if you wanted one.
- ComputerGuru 7y agoCPU utilization is a zero-sum game. If you need to use the CPU to calculate checksums or do packet segmentation then it’s that much less CPU available for TLS.
- alfalfasprout 7y agoSo not quite... a lot of modern CPUs have crypto primitives implemented in hardware that allow other instructions to run simultaneously on the same core (taking advantage of hyperthreading and out of order execution).
- geocar 7y agoThat's one way to look at it. Another way is if it takes a couple CPUs to run my application, a CPU or two to drive the storage, and a CPU to do TLS, why would I also spend a CPU on TCP if my network card already has one that does that? That's a little bit like what programmers are talking about when they are talking about "multi-core programming", except those are general-purpose "cores", and (presumably) these "cores" can only handle doing TCP.