Hi Karsten, we still believe that the statistics are useful. However we also agree with Rob that since more and more relays report data the scatter plot becomes confusing. I think some kind of aggregation would be helpful.
In one of our previous papers we assessed the performance impact of simultaneous TCP connections in overlay networks [1]. There we found that the occurring performance degradation is hard(er) to solve when connections are used bidirectionally -- which is the motivation for these statistics. From the current results I would presume that this is the case in Tor most of the time. In Future developments the statistics could become helpful. Cheers, Florian. [1] D. Marks, F. Tschorsch, and B. Scheuermann, "Unleashing Tor, BitTorrent Co.: How to relieve TCP deficiencies in overlays," in 35th IEEE Conference on Local Computer Networks (LCN'10), 2010, pp. 320–323. On 16/12/13 05:34, Rob Jansen wrote: > Hey Karsten, > > I think the statistics could be useful, though I don't currently utilize > them. I think the current presentation is somewhat confusing. Perhaps we can > try to brainstorm some alternative ways to present the data if the decision > is that we should keep it around. > > Best, > Rob > > On Dec 9, 2013, at 12:43 PM, Karsten Loesing wrote: > >> Björn, Florian, >> >> a few years back (in 2010, to be precise) we added statistics to >> little-t-tor reporting what fraction of connections is used >> uni-/bidirectionally. Quoting dir-spec.txt: >> >> "conn-bi-direct" YYYY-MM-DD HH:MM:SS (NSEC s) BELOW,READ,WRITE,BOTH NL >> [At most once] >> >> Number of connections, split into 10-second intervals, that are >> used uni-directionally or bi-directionally as observed in the NSEC >> seconds (usually 86400 seconds) before YYYY-MM-DD HH:MM:SS. Every >> 10 seconds, we determine for every connection whether we read and >> wrote less than a threshold of 20 KiB (BELOW), read at least 10 >> times more than we wrote (READ), wrote at least 10 times more than >> we read (WRITE), or read and wrote more than the threshold, but >> not 10 times more in either direction (BOTH). After classifying a >> connection, read and write counters are reset for the next >> 10-second interval. >> >> These statistics are disabled by default, but when they are enabled, >> relays publish them in their extra-info descriptors. And quite a few >> relays do that. Here's a (bad) visualization (that used to be slightly >> less bad when fewer relays published these statistics): >> >> https://metrics.torproject.org/performance.html#connbidirect >> >> Here's the question: Is there still value in having these statistics? I >> recall that they were useful in 2010, but will that still be the case in >> 2013? >> >> If the answer is "yes", never mind. >> >> If the answer is "no", I'd create a ticket and submit a patch to remove >> code parts from little-t-tor, and I'd remove the not-really-useful graph >> from the metrics website. >> >> Cc'ing Rob, Aaron, and Roger as the people who typically have an >> interest in these kinds of statistics. If other tor-dev@ people have an >> opinion on this, please raise your voice! >> >> All the best, >> Karsten > _______________________________________________ tor-dev mailing list [email protected] https://lists.torproject.org/cgi-bin/mailman/listinfo/tor-dev
