3 ms·
The "TCP packet retransmit" one is interesting, because it's a parameter you can set in your socket library or kernel. On Linux the default minimum RTO is 200m
by thrownaway2424 12y ago
The "TCP packet retransmit" one is interesting, because it's a parameter you can set in your socket library or kernel. On Linux the default minimum RTO is 200ms, even if the RTT of the connection is < 1ms. For local networking you really, really want to reduce the minimum RTO to a much smaller number. If you don't, random packet loss is going to dominate your tail latency.
- drdaeman 12y agoFor local networking, packet loss is, in most cases, a sign something somewhere isn't doing well. So, maybe, it's better notice it sooner than bump into possible unexpected problems later.
- theonewolf 12y agoI think for things like WiFi networks this could help immensely. Extremely long tail latencies are observed which reach a second or more in those networks when some interference causes loss. It would be much better to react quicker than the eternity of 200ms (if that is the default).
- thrownaway2424 12y agoNot really. A busy network has a million little buffers and things where your packet might get dropped but succeed 1ms later.
- wtallis 12y agoBut those buffers are also often huge and your packet could still come out the other end of one of them 20ms (or 2s, if it's a cable or DSL modem) later. You still want to treat it as evidence of congestion, though.