Bug #713
closed
Shaper Wizard: When backlogged, high priority queues get zero bandwidth
Added by Aaron Berland over 14 years ago.
Updated almost 14 years ago.
Category:
Traffic Shaper (ALTQ)
Description
Shaper wizard results for basic config:
qOthersLow - LinkShare: 5%, 500ms, 5% < This is a flat curve and redundant., 5% for the first 500ms and then 5% after that.
qOthersHigh - LinkShare: 0b, 200ms, 10% < No traffic allowed until service curve opens up!
qAck - LinkShare: 0b, 100ms, 20% < No ACKs allowed until service curve opens up!
Fix: remove m1 and d service curve values to allow traffic to flow immediately. Advanced users can set service curves if they want/need them. Don't prevent traffic from flowing by default!
Files
Can you please be more detailed on what the error is?
There is no error message output.
The shaper config functions, but logically is not correct. During congestion, having a service curve start at 0 bandwidth drops packets so the low priority queue gets the bandwidth while the higher priority queues are blocked for a moment. Performance is dramatically reduced for acks and high priority traffic during congestion.
I believe this is why qDefault and qOthersLow can get better performance than the higher priority queues and not allow maximum performance.
- Status changed from New to Feedback
- % Done changed from 0 to 100
I can confirm this as resolved. The qACK and QOthersHigh get created without the Link Share M1 or D options set now. So qACK and QOthersHigh traffic does not get starved for a certain number of ms when the queue is full.
Tested with Dec 2nd nanobsd snapshot.
Thanks Ermal
Josh
- Status changed from Feedback to Resolved
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