[PATCH v10 0/7] Lcore variables

[Stephen Hemminger]

On Fri, 11 Oct 2024 10:18:54 +0200
Mattias Rönnblom <mattias.ronnblom at ericsson.com> wrote:

> This patch set introduces a new API <rte_lcore_var.h> for static
> per-lcore id data allocation.
> 
> Please refer to the <rte_lcore_var.h> API documentation for both a
> rationale for this new API, and a comparison to the alternatives
> available.
> 
> The adoption of this API would affect many different DPDK modules, but
> the author updated only a few, mostly to serve as examples in this
> RFC, and to iron out some, but surely not all, wrinkles in the API.
> 
> The question on how to best allocate static per-lcore memory has been
> up several times on the dev mailing list, for example in the thread on
> "random: use per lcore state" RFC by Stephen Hemminger.
> 
> Lcore variables are surely not the answer to all your per-lcore-data
> needs, since it only allows for more-or-less static allocation. In the
> author's opinion, it does however provide a reasonably simple and
> clean and seemingly very much performant solution to a real problem.
> 
> Mattias Rönnblom (7):
>   eal: add static per-lcore memory allocation facility
>   eal: add lcore variable functional tests
>   eal: add lcore variable performance test
>   random: keep PRNG state in lcore variable
>   power: keep per-lcore state in lcore variable
>   service: keep per-lcore state in lcore variable
>   eal: keep per-lcore power intrinsics state in lcore variable
> 
>  MAINTAINERS                                   |   6 +
>  app/test/meson.build                          |   2 +
>  app/test/test_lcore_var.c                     | 436 ++++++++++++++++++
>  app/test/test_lcore_var_perf.c                | 257 +++++++++++
>  config/rte_config.h                           |   1 +
>  doc/api/doxy-api-index.md                     |   1 +
>  .../prog_guide/env_abstraction_layer.rst      |  43 +-
>  doc/guides/rel_notes/release_24_11.rst        |  14 +
>  lib/eal/common/eal_common_lcore_var.c         |  85 ++++
>  lib/eal/common/meson.build                    |   1 +
>  lib/eal/common/rte_random.c                   |  28 +-
>  lib/eal/common/rte_service.c                  | 117 ++---
>  lib/eal/include/meson.build                   |   1 +
>  lib/eal/include/rte_lcore_var.h               | 389 ++++++++++++++++
>  lib/eal/version.map                           |   3 +
>  lib/eal/x86/rte_power_intrinsics.c            |  17 +-
>  lib/power/rte_power_pmd_mgmt.c                |  35 +-
>  17 files changed, 1343 insertions(+), 93 deletions(-)
>  create mode 100644 app/test/test_lcore_var.c
>  create mode 100644 app/test/test_lcore_var_perf.c
>  create mode 100644 lib/eal/common/eal_common_lcore_var.c
>  create mode 100644 lib/eal/include/rte_lcore_var.h
> 


Are there any trace points in this code? Would be good to have.
Also some optional statistics for telemetry use.
I would presume this is not intended as a hot path API; therefore
it would be ok to always keep statistics.