Re: [PATCH v4] lib/librte_meter: add meter configuration profile

[Thomas Monjalon <thomas@monjalon.net>]

08/01/2018 16:43, Jasvinder Singh:
> From: Cristian Dumitrescu <cristian.dumitrescu@intel.com>
> 
> This patch adds support for meter configuration profiles.
> Benefits: simplified configuration procedure, improved performance.
> 
> Q1: What is the configuration profile and why does it make sense?
> A1: The configuration profile represents the set of configuration
>     parameters for a given meter object, such as the rates and sizes for
>     the token buckets. The configuration profile concept makes sense when
>     many meter objects share the same configuration, which is the typical
>     usage model: thousands of traffic flows are each individually metered
>     according to just a few service levels (i.e. profiles).
> 
> Q2: How is the configuration profile improving the performance?
> A2: The performance improvement is achieved by reducing the memory
>     footprint of a meter object, which results in better cache utilization
>     for the typical case when large arrays of meter objects are used. The
>     internal data structures stored for each meter object contain:
>        a) Constant fields: Low level translation of the configuration
>           parameters that does not change post-configuration. This is
>           really duplicated for all meters that use the same
>           configuration. This is the configuration profile data that is
>           moved away from the meter object. Current size (implementation
>           dependent): srTCM = 32 bytes, trTCM = 32 bytes.
>        b) Variable fields: Time stamps and running counters that change
>           during the on-going traffic metering process. Current size
>           (implementation dependant): srTCM = 24 bytes, trTCM = 32 bytes.
>           Therefore, by moving the constant fields to a separate profile
>           data structure shared by all the meters with the same
>           configuration, the size of the meter object is reduced by ~50%.
> 
> Signed-off-by: Cristian Dumitrescu <cristian.dumitrescu@intel.com>
> Signed-off-by: Jasvinder Singh <jasvinder.singh@intel.com>

Applied for 18.05 (was postponed to preserve 18.02 ABI), thanks.