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Prop 324: Document new cc_ewma_ss consensus parameter.

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Mike Perry 2022-08-10 22:13:38 +00:00 committed by David Goulet
parent 7c186cf1e5
commit 07c731e836
1 changed files with 14 additions and 3 deletions
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17
proposals/324-rtt-congestion-control.txt
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@ -169,10 +169,12 @@ Moving Average with alpha = 2/(N+1):
N_EWMA = BDP*2/(N+1) + N_EWMA_prev*(N-1)/(N+1).
Flow control rate limiting uses this function
Flow control rate limiting uses this function.
For both RTT and SENDME BDP estimation, N is the number of SENDME acks
between congestion window updates, divided by the value of consensus
During Slow Start, N is set to `cc_ewma_ss`, for RTT estimation.
After Slow Start, for both RTT and SENDME BDP estimation, N is the number
of SENDME acks between congestion window updates, divided by the value of consensus
parameter 'cc_ewma_cwnd_pct', and then capped at a max of 'cc_ewma_max',
but always at least 2:
@ -1293,6 +1295,15 @@ These are sorted in order of importance to tune, most important first.
congestion, to avoid overloading slow relays. Values of 10 or 20
were best.
cc_ewma_ss:
- Description: This specifies the N in N_EWMA smoothing of RTT during
Slow Start.
- Range: [2, INT32_MAX]
- Default: 2
- Tuning Values: [2,4]
- Shadow Tuning Results:
Setting this to 2 helped reduce overshoot during Slow Start.
cc_cwnd_inc:
- Description: How much to increment the congestion window by during
steady state, every cwnd.