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Update the ratio calculation to prefer faster measurements.

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Also: simplify complicated filtering steps, always take the
most recent measurement, and use slightly smaller file sizes
based on measurements.
This commit is contained in:
Mike Perry 2009-07-14 20:47:51 -07:00
parent 011b732436
commit 3a1b9526f8
1 changed files with 12 additions and 16 deletions
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28
doc/spec/proposals/161-computing-bandwidth-adjustments.txt
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@ -45,12 +45,11 @@ Status: Open
file is downloaded via these circuits. The file sizes are set based file is downloaded via these circuits. The file sizes are set based
on node percentile rank as follows: on node percentile rank as follows:
0-10: 4M 0-10: 2M
10-20: 2M 10-20: 1M
20-30: 1M 20-30: 512k
30-50: 512k 30-50: 256k
50-75: 256k 50-100: 128k
75-100: 128k
These sizes are based on measurements performed during test scans. These sizes are based on measurements performed during test scans.
@ -72,8 +71,8 @@ Status: Open
with capacity of one standard deviation below a node's average with capacity of one standard deviation below a node's average
are also removed. are also removed.
The final ratio result will be the unfiltered ratio if it is The final ratio result will be greater of the unfiltered ratio
close to 1.0, otherwise it will be the filtered ratio. and the filtered ratio.
6. Pseudocode for Ratio Calculation Algorithm 6. Pseudocode for Ratio Calculation Algorithm
@ -88,11 +87,8 @@ Status: Open
BW_measured(N) = MEAN(b | b is bandwidth of a stream through N) BW_measured(N) = MEAN(b | b is bandwidth of a stream through N)
Bw_stddev(N) = STDDEV(b | b is bandwidth of a stream through N) Bw_stddev(N) = STDDEV(b | b is bandwidth of a stream through N)
Bw_avg(S) = MEAN(b | b = BW_measured(N) for all N in S) Bw_avg(S) = MEAN(b | b = BW_measured(N) for all N in S)
Normal_Routers(S) = {N | Bw_measured(N)/Bw_avg(S) > 0.5 }
for N in S: for N in S:
Normal_Streams(N) = Normal_Streams(N) = {stream via N | bandwidth >= BW_measured(N)}
{stream via N | all nodes in stream not in {Normal_Routers(S)-N}
and bandwidth > BW_measured(N)-Bw_stddev(N)}
BW_Norm_measured(N) = MEAN(b | b is a bandwidth of Normal_Streams(N)) BW_Norm_measured(N) = MEAN(b | b is a bandwidth of Normal_Streams(N))
Bw_net_avg(Slices) = MEAN(BW_measured(N) for all N in Slices) Bw_net_avg(Slices) = MEAN(BW_measured(N) for all N in Slices)
@ -100,9 +96,9 @@ Status: Open
for N in all Slices: for N in all Slices:
Bw_net_ratio(N) = Bw_measured(N)/Bw_net_avg(Slices) Bw_net_ratio(N) = Bw_measured(N)/Bw_net_avg(Slices)
Bw_Norm_net_ratio(N) = Bw_measured2(N)/Bw_Norm_net_avg(Slices) Bw_Norm_net_ratio(N) = BW_Norm_measured(N)/Bw_Norm_net_avg(Slices)
ResultRatio(N) = ClosestToOne(Bw_net_ratio(N), Bw_Norm_net_ratio(N)) ResultRatio(N) = MAX(Bw_net_ratio(N), Bw_Norm_net_ratio(N))
7. Security implications 7. Security implications
@ -142,8 +138,8 @@ Status: Open
by another script that uses them to produce network-wide averages by another script that uses them to produce network-wide averages
and calculate ratios as per the algorithm in section 6. Because nodes and calculate ratios as per the algorithm in section 6. Because nodes
may shift in capacity, they may appear in more than one slice and/or may shift in capacity, they may appear in more than one slice and/or
appear more than once in the file set. The line that yields a ratio appear more than once in the file set. The most recently measured
closest to 1.0 will be chosen in this case. line will be chosen in this case.
9. Integration with Proposal 160 9. Integration with Proposal 160