Hi again, > On 2 Aug 2019, at 08:18, Rob Jansen <rob.g.jan...@nrl.navy.mil> wrote: > >> On Jul 31, 2019, at 7:34 PM, teor <t...@riseup.net> wrote: >> >> Can you define "goodput"? > > Application-level throughput, i.e., bytes transferred in packet payloads but > not counting packet headers or retransmissions. In our case I mean the number > of bytes that Tor reports in the BW controller event. > >> How is it different to the bandwidth reported by a standard speed test? > > I believe that iperf also reports goodput as defined above. > >> How is it different to the bandwidth measured by sbws? > > I am not an expert on sbws, but I believe it also measures goodput. > >> Where is your server? > > West coast US. > >> How do you expect the location of your server to affect your results? > > I expect that the packet loss that occurs between my measurement machine and > the target may limit the goodput I am able to achieve, and packet loss tends > to occur more frequently on links with higher latency.
Tor's stream window also limits the goodput of a single stream. The in-flight bandwidth is limited to 500 cells * 498 RELAY_DATA cell goodput bytes = 243 kBytes > I plan to use multiple sockets (as standard speed testing tools like iperf > do) and multiple circuits to try to mitigate the effects. Good. sbws only uses one stream at a time, and its streams are open for 5-10 seconds. > Note that this is meant to be a fairly simple experiment, not a complete > measurement system. Of course I won't be able to measure more than the > bandwidth capacity of my measurement machine, but many relays already carry > significant load so I'll just be giving them a boost. Sounds like a useful experiment. If using multiple circuits for 20 seconds makes a significant difference to some relays, we should consider changing sbws to: * use multiple circuits, * use 2 streams per circuit (to fill each circuit window), and * run each test for 20 seconds. Or we could modify the relay bandwidth self-test to: * use significantly more bandwidth, and try to find the bandwidth limit for each relay, and * run each test for 20 seconds. (The relay bandwidth self-test uses DROP cells on multiple circuits, so stream windows don't apply.) T _______________________________________________ tor-relays mailing list tor-relays@lists.torproject.org https://lists.torproject.org/cgi-bin/mailman/listinfo/tor-relays
