[dpdk-dev] meter: excess token bucket update in srtcm

Nikhil Jagtap nikhil.jagtap at gmail.com
Wed Aug 31 12:02:16 CEST 2016


Hi,

As per srTCM RFC 2697, we should be updating the E bucket only after the C
bucket overflows.
"Thereafter, the token counts Tc and Te are updated CIR times per second as
follows:
     o If Tc is less than CBS, Tc is incremented by one, else
     o if Te is less then EBS, Te is incremented by one, else
     o neither Tc nor Te is incremented."

However in the current DPDK implementation of srTCM, we are updating both
the buckets simultaneously at the same rate (CIR). This will result in a
token accumulation rate of (2*CIR). This seems like a bug to me. Can you
confirm this?

Nikhil


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