Reduce the number of 50 KiB downloads
On legacy/trac#33076 (moved) we discussed whether we should kill the 50 KiB downloads in deployed OnionPerfs and only keep the 1 MiB and 5 MiB downloads. The primary reason would be that our throughput graphs would be based on five times as many data points per day, because they only include 1 MiB and 5 MiB downloads, but not 50 KiB downloads. This would not affect our circuit round-trip latencies graphs which include all three downloaded file sizes.
The main reason against killing 50 KiB downloads is that OnionPerfs would consume more bandwidth and also put more load on the Tor network. Let's consider two scenarios with and without 50 KiB downloads. In both scenarios we're making a new download every 5 minutes, randomly chosen with a weight of 1.0 for 5 MiB runs, 2.0 for 1 MiB runs, and either 12.0 or 0.0 for 50 KiB runs:
With 50 KiB downloads we're downloading on average
12/15 * 50 KiB + 2/15 * 1 MiB + 1/15 * 5 MiB = 517 KiBevery 5 minutes, or
517 * 8 * 1024 / (300 * 1000) = 14 kbps.
Without 50 KiB downloads we're downloading on average
2/3 * 1 MiB + 1/3 * 5 MiB = 2389 KiBevery 5 minutes, or
2389 * 8 * 1024 / (300 * 1000) = 65 kbps.
These numbers are both tiny in comparison to the overall network capacity and to other services like the bandwidth scanners.
I'm going to make this change and deploy it on new OnionPerf instances tomorrow, unless I hear objections here.