young Fedora torrents spread data too slowly

[John Reiser]

Young torrents on http://torrent.fedoraproject.org/ spread data too slowly.
At 0500 UTC on Sat.Oct.11, there was 1 seed and 14 leeches, all at 13% done.
At 1300 UTC on Sat.Oct.11, there was 1 seed and 31 leeches, all at 55% done.
This is for F10-Snap1-x86_64-Live.
I turned my machine off for the night (US PDT), powered on in the morning,
and within half an hour had caught up to all leeches at 57% done.
I use tranmsissionbt, and I saw that the seed was sending pieces of 256 KiB
to me at 2.5 KiB/s, taking almost two minutes per piece (and then "pausing.")

It seems to me that torrent.fedoraproject.org is overloaded, and that a change
in policy would give sooner completion to everybody, even without more resources.
Namely, give priority service to young torrents (less than 1 day old), and
while there are less than 2 other seeds then give even higher priority service
to the fastest sqrt(N) leeches.  The current policy of serving each client alike
results in everybody waiting for the one overloaded seed.  Increasing the size
of the swarm does not decrease anybody's completion time.
Instead, the sooner that there are >=2 other seeds, then the sooner that
*all* leeches complete, even though the fastest may complete much sooner
than others, and even though some greedy new seeds may quit the swarm
soon after reaching 100%.

Implementing such policies may require using a seeder/tracker that serves
more than one torrent at a time, but this feature is available
in a number of trackers, including Transmission.

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