Agnostic_baker: Add profiling

What

Parent MR: !16968 (merged)

We plug the profiler in the agnostic baker with this MR.

Why

To showcase that the agnostic baker logic does not add sensible overhead to the baking mechanism.

How

By creating an agnostic baker profiler (independent of the protocol code of course) which outputs in the same client directory (it made sense to put it there since this is where baking_profiling is located) and by profiling all calls that could be costly (RPC ones + retrieving protocol plugin + stopping/spawning bakers).

I decided to profile everything as Notice as there is not a lot of calls being made anyways.

Manually testing the MR

To showcase the interesting part, which is when we have a protocol migration, one can tweak the tezt code a bit:

• in tezt/lib_tezos/agnostic_baker.ml run function, add the environment variables meant to trigger profiling (PROFILING=Debug PROFILING_BACKEND=txt) by adding the ~env parameter to the daemon run function at the end:

  run
    ~env:
      (String_map.of_list
         [("PROFILING", "Debug"); ("PROFILING_BACKEND", "txt")])
    ?event_level
    ?event_sections_levels
    agnostic_baker
    {ready = false}
    arguments
    ~on_terminate
    ?runner

Now, go to any of the tests from tezt/tests/protocol_migration.ml or tezt/tests/agnostic_baker_test.ml and add a big sleep to the tests and then while the tests are running, go into the client directories used by the agnostic bakers to get the profiling reports. This is what I got for the protocol_migration one:

TEZOS_PPX_PROFILER=profiling make

dune exec tezt/tests/main.exe -- --file protocol_migration.ml -v --title 'agnostic baker forked migration blocks from r022 to alpha'

As you can see, the resources needed are very small (not impactful at all).

This is what I got for the agnostic_baker_test.ml:

2025-03-21T13:45:54.016-00:00
BLiu1Nb7fvEPviHUJfhxXLdvKfDAN5wL7LvBPqcrBLYCKMLNWmU ............................ 1         1000.299ms   4%
  get_current_period ........................................................... 1            1.378ms 135%
  maybe_kill_old_baker ......................................................... 1            0.001ms 210%
  get_next_protocol_hash ....................................................... 1            1.890ms  43%
  get_block_hash ............................................................... 1            2.175ms  28%
2025-03-21T13:45:55.016-00:00
BLMuNk2XT7bxxNBV2pkF467Sp2HwjEbSNjPNXDyRM8Ro5K55nqB ............................ 1          998.101ms   5%
  get_current_period ........................................................... 1            1.053ms  31%
  maybe_kill_old_baker ......................................................... 1            0.002ms  94%
  get_next_protocol_hash ....................................................... 1            1.691ms  44%
  get_level .................................................................... 1            0.558ms  30%
  hot_swap_baker ............................................................... 1            1.293ms 115%
    proto_plugin_for_protocol .................................................. 1            0.003ms 162%
  get_block_hash ............................................................... 1            1.417ms 130%
2025-03-21T13:45:56.015-00:00
BLzozs8odZznq9RNayrXPbL5EB4vWwoPwcmJFm2QLprWE59eTEV ............................ 1         1003.608ms   4%
  get_current_period ........................................................... 1            2.235ms  36%
  maybe_kill_old_baker ......................................................... 1            2.763ms  72%
    get_level .................................................................. 1            2.761ms  72%
  get_next_protocol_hash ....................................................... 1            2.167ms  26%
  get_block_hash ............................................................... 1            3.035ms 107%
2025-03-21T13:45:57.018-00:00
BKx2DQHrYszPmBRXCR5Sdm4JPnros2HMauVXXAWAwHWWTyqyRjR ............................ 1         1002.172ms   6%
  get_current_period ........................................................... 1            5.969ms 104%
  maybe_kill_old_baker ......................................................... 1            3.380ms  57%
    get_level .................................................................. 1            3.376ms  57%
  get_next_protocol_hash ....................................................... 1            2.289ms  32%
  get_block_hash ............................................................... 1            4.110ms 107%
2025-03-21T13:45:58.020-00:00
BMctQ4DsgRc8yyf1ozxuCASDu3yfm9c5tpBbUCy3vsbFaWEY42V ............................ 1         1010.376ms   7%
  get_current_period ........................................................... 1            3.797ms 103%
  maybe_kill_old_baker ......................................................... 1            3.918ms  76%
    get_level .................................................................. 1            2.261ms  61%
    kill old baker ............................................................. 1            1.053ms  96%
  get_next_protocol_hash ....................................................... 1            2.843ms 109%
  get_block_hash ............................................................... 1            6.115ms  69%
2025-03-21T13:45:59.031-00:00
BKsJdp8kEG1kebMKkPFPKdHNSw5mbjUfp7ufbqEm7SNmu42HoAp ............................ 1         1001.792ms   5%
  get_current_period ........................................................... 1            2.934ms  80%
  maybe_kill_old_baker ......................................................... 1            0.001ms 210%
  get_next_protocol_hash ....................................................... 1            1.267ms 119%
  get_block_hash ............................................................... 1            7.764ms  77%

Checklist

• Document the interface of any function added or modified (see the coding guidelines)
• Document any change to the user interface, including configuration parameters (see node configuration)
• Provide automatic testing (see the testing guide).
• For new features and bug fixes, add an item in the appropriate changelog (docs/protocols/alpha.rst for the protocol and the environment, CHANGES.rst at the root of the repository for everything else).
• Select suitable reviewers using the Reviewers field below.
• Select as Assignee the next person who should take action on that MR