[GitHub] [pulsar] frankjkelly commented on issue #15905: [Doc] Threshold Shedder documentation - need to add documentation on the individual weights

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frankjkelly commented on issue #15905:
URL: https://github.com/apache/pulsar/issues/15905#issuecomment-1158999729

   @Demogorgon314 thanks the example is super helpful and perhaps could be added to the documentation?
   
   As regards the weights - isn't the purpose of the documentation so that I don't have to read the code / configuration files? 
   Also what are the range of values to set to weights? 0 to 1.0, 1.0 to 100.0?
   
   I also realized another question - when I read the code I was surprised to see when the resource weighting is employed here
   https://github.com/apache/pulsar/blob/a812f29bab93a5e841a9b3c3190fca343fab6e71/pulsar-broker/src/main/java/org/apache/pulsar/broker/loadbalance/impl/ThresholdShedder.java#L160-L164
   
   The the `max` of the `resource * resourceWeight` is used to determine  overload
   https://github.com/apache/pulsar/blob/a2559923877b005e4eec797214d1bcd9fb378df7/pulsar-common/src/main/java/org/apache/pulsar/policies/data/loadbalancer/LocalBrokerData.java#L253-L255
   
   Usually when I see a "weight" it is not a winner-take-all approach but some scoring that takes each resource & weight into account. In addition the calculation results are not normalized on a scale of 0 to 1 or 0 to 100 - the problem without normalizing 
   
   For example I could set loadBalancerCPUResourceWeight to 1000.0 and then the threshold would have to be scaled appropriately. 
   I see a divide by `100` here https://github.com/apache/pulsar/blob/a2559923877b005e4eec797214d1bcd9fb378df7/pulsar-common/src/main/java/org/apache/pulsar/policies/data/loadbalancer/LocalBrokerData.java#L253-L255
   but without bounds on the weights that's not going to normalize things.
   
   So even when I look at the config files I still need to read the code to figure out how those weights will be used.
   
   Anyway I am excited to use this feature and appreciate your insight and help.
   
   Thanks!
   
   


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