[RFC 2/2] eal: add high-performance timer facility

[Stephen Hemminger]

On Tue, 28 Feb 2023 10:39:16 +0100
Mattias Rönnblom <mattias.ronnblom at ericsson.com> wrote:

> The htimer library attempts at providing a timer facility with roughly
> the same functionality, but less overhead and better scalability than
> DPDK timer library.
> 
> The htimer library employs per-lcore hierachical timer wheels and a
> message-based synchronization/MT-safety scheme.
> 
> Signed-off-by: Mattias Rönnblom <mattias.ronnblom at ericsson.com>

I like this but:
  - need to have one timer infrastructure, having multiple will lead to confusion
    and overlap in user applications. I.e can they be mixed, what happens if X and Y...

  - best to keep original API available.

  - ok to drop the rte_alt_timer since it was always experimental.

  - would be good to have API using consistent known time (nanoseconds?) rather
    than TSC cycles.

  - there could be use cases for REALTIME as well as MONOTONIC types.