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nh2 | 27 days ago
To measure other overhead of what's claimed (TCP the protocol being slow), one should exclude other things that necessarily affect alternative protocols as well (e.g. latency) as much as possible, which is what this does.
wtallis|27 days ago
But it's much more complicated than that; TCP interacts with latency and congestion and packet loss as both cause and effect. If you're testing TCP without sending traffic over real networks that have their own buffering and congestion control and packet reordering and loss, you're going to miss all of the most important dynamics affecting real-world performance. For example, you're not going to measure how multiplexing multiple data streams onto one TCP connection allows head of line blocking to drastically inflate the impact of a lost or reordered packet, because none of that happens when all you're testing is the speed at which your kernel can context-switch packets between local processes.
And all of that is without even beginning to touch on what happens to wireless networks.
nh2|27 days ago
Almost like it makes the point that arguing about "high performance" is useless without saying what that means.
That said:
> you're not going to measure how multiplexing multiple data streams onto one TCP connection
Of course not: When I want to argue against "TCP is not a high performance protocol", why would I want to measure some other protocol that multiplexes connections over TCP? That is not measuring the performance of TCP.
I could conjure any protocol that requires acknowledgement from the other side for each emitted packet before sending the next, and then claim "UDP is not high performance" when running that over UDP - that doesn't make sense.