when using remote-reader + vpcd, the request is sent by doing 2 sendall operations on the socket (one for the length, another for the data). this splits the request into 2 TCP segments, meaning Nagle's algorithm kicks in and holds the second segment until an ACK for the first is received. this introduces an unnecessary RTT.
remote-reader also does this on their end, which introduces another RTT. these RTTs can end up representing most of the time the user spends waiting (with Android they're usually on the order of hundreds of milliseconds).
in conclusion, this makes overall operation ~3x faster. for example, in my case pkcs15-tool -c drops from 6.3 seconds to about 2 seconds.
frankmorgner
commented
1 year ago
when using remote-reader + vpcd, the request is sent by doing 2
sendalloperations on the socket (one for the length, another for the data). this splits the request into 2 TCP segments, meaning Nagle's algorithm kicks in and holds the second segment until an ACK for the first is received. this introduces an unnecessary RTT.remote-reader also does this on their end, which introduces another RTT. these RTTs can end up representing most of the time the user spends waiting (with Android they're usually on the order of hundreds of milliseconds).
in conclusion, this makes overall operation ~3x faster. for example, in my case
pkcs15-tool -cdrops from 6.3 seconds to about 2 seconds.