[v3,0/4] lcore telemetry improvements

  This is a follow up on previous work by Kevin Laatz:

http://patches.dpdk.org/project/dpdk/list/?series=24658&state=*

This series is aimed at allowing DPDK applications to expose their CPU
usage stats in the DPDK telemetry under /eal/lcore/info. This is a much
more basic and naive approach which leaves the cpu cycles accounting
completely up to the application.

For reference, I have implemented a draft patch in OvS to use
rte_lcore_register_usage_cb() and report the already available busy
cycles information.

https://github.com/rjarry/ovs/commit/327db12c751be0375fcfed5e44b6065bcfb75c82

Changes since v2:

- Fixed typos in docstrings.
- Used if (xxx != NULL) instead of if (xxx) test convention.
- Guarded against an unlikely race if rte_lcore_dump() is called by
  a thread while another one calls rte_lcore_register_usage_cb(NULL).
- s/utilization/usage/
- Fixed build on Windows.

Changes since v1:

- The cpuset field in telemetry is now a JSON list of CPU ids.
- Applications must now report their raw CPU cycles counts. The busyness
  ratio and rate of change is left to external monitoring tools.
- Renamed show lcores -> dump_lcores in testpmd.

Robin Jarry (4):
  eal: add lcore info in telemetry
  eal: allow applications to report their cpu cycles usage
  testpmd: add dump_lcores command
  testpmd: report lcore usage

 app/test-pmd/5tswap.c             |   5 +-
 app/test-pmd/cmdline.c            |   3 +
 app/test-pmd/csumonly.c           |   6 +-
 app/test-pmd/flowgen.c            |   2 +-
 app/test-pmd/icmpecho.c           |   6 +-
 app/test-pmd/iofwd.c              |   5 +-
 app/test-pmd/macfwd.c             |   5 +-
 app/test-pmd/macswap.c            |   5 +-
 app/test-pmd/noisy_vnf.c          |   4 +
 app/test-pmd/rxonly.c             |   5 +-
 app/test-pmd/shared_rxq_fwd.c     |   5 +-
 app/test-pmd/testpmd.c            |  39 ++++++++-
 app/test-pmd/testpmd.h            |  14 +++-
 app/test-pmd/txonly.c             |   7 +-
 lib/eal/common/eal_common_lcore.c | 131 +++++++++++++++++++++++++++++-
 lib/eal/include/rte_lcore.h       |  29 +++++++
 lib/eal/version.map               |   1 +
 17 files changed, 242 insertions(+), 30 deletions(-)
  

On 2022-11-29 16:33, Robin Jarry wrote:
> This is a follow up on previous work by Kevin Laatz:
> 
> http://patches.dpdk.org/project/dpdk/list/?series=24658&state=*
> 
> This series is aimed at allowing DPDK applications to expose their CPU
> usage stats in the DPDK telemetry under /eal/lcore/info. This is a much
> more basic and naive approach which leaves the cpu cycles accounting
> completely up to the application.
> 

This seems like a reasonable approach to me.

DPDK needs to have more OS-type constructs for a feature like this to be 
implemented, without application involvement. I would love for this to 
happen, but we aren't there yet.

> For reference, I have implemented a draft patch in OvS to use
> rte_lcore_register_usage_cb() and report the already available busy
> cycles information.
> 
> https://github.com/rjarry/ovs/commit/327db12c751be0375fcfed5e44b6065bcfb75c82
> 
> Changes since v2:
> 
> - Fixed typos in docstrings.
> - Used if (xxx != NULL) instead of if (xxx) test convention.
> - Guarded against an unlikely race if rte_lcore_dump() is called by
>    a thread while another one calls rte_lcore_register_usage_cb(NULL).
> - s/utilization/usage/
> - Fixed build on Windows.
> 
> Changes since v1:
> 
> - The cpuset field in telemetry is now a JSON list of CPU ids.
> - Applications must now report their raw CPU cycles counts. The busyness
>    ratio and rate of change is left to external monitoring tools.
> - Renamed show lcores -> dump_lcores in testpmd.
> 
> Robin Jarry (4):
>    eal: add lcore info in telemetry
>    eal: allow applications to report their cpu cycles usage
>    testpmd: add dump_lcores command
>    testpmd: report lcore usage
> 
>   app/test-pmd/5tswap.c             |   5 +-
>   app/test-pmd/cmdline.c            |   3 +
>   app/test-pmd/csumonly.c           |   6 +-
>   app/test-pmd/flowgen.c            |   2 +-
>   app/test-pmd/icmpecho.c           |   6 +-
>   app/test-pmd/iofwd.c              |   5 +-
>   app/test-pmd/macfwd.c             |   5 +-
>   app/test-pmd/macswap.c            |   5 +-
>   app/test-pmd/noisy_vnf.c          |   4 +
>   app/test-pmd/rxonly.c             |   5 +-
>   app/test-pmd/shared_rxq_fwd.c     |   5 +-
>   app/test-pmd/testpmd.c            |  39 ++++++++-
>   app/test-pmd/testpmd.h            |  14 +++-
>   app/test-pmd/txonly.c             |   7 +-
>   lib/eal/common/eal_common_lcore.c | 131 +++++++++++++++++++++++++++++-
>   lib/eal/include/rte_lcore.h       |  29 +++++++
>   lib/eal/version.map               |   1 +
>   17 files changed, 242 insertions(+), 30 deletions(-)
>