From 380f2067fd43338c740fd06f45c3e26d236778a6 Mon Sep 17 00:00:00 2001
From: Gabriel Moise <gabriel.moise@trili.tech>
Date: Mon, 3 Mar 2025 15:35:46 +0000
Subject: [PATCH 1/6] Agnostic_baker: Add agnostic baker profiler module

---
 manifest/product_octez.ml                       |  4 ++++
 opam/octez-experimental-agnostic-baker-lib.opam |  2 +-
 src/bin_agnostic_baker/main_agnostic_baker.ml   |  8 ++++++++
 .../agnostic_baker_profiler.ml                  | 17 +++++++++++++++++
 .../agnostic_baker_profiler.mli                 | 16 ++++++++++++++++
 src/lib_agnostic_baker/daemon.ml                |  8 ++++++++
 src/lib_agnostic_baker/dune                     |  8 ++++++--
 7 files changed, 60 insertions(+), 3 deletions(-)
 create mode 100644 src/lib_agnostic_baker/agnostic_baker_profiler.ml
 create mode 100644 src/lib_agnostic_baker/agnostic_baker_profiler.mli

diff --git a/manifest/product_octez.ml b/manifest/product_octez.ml
index d1d286db12ae..e3e5e6641269 100644
--- a/manifest/product_octez.ml
+++ b/manifest/product_octez.ml
@@ -5343,11 +5343,14 @@ let _octez_scoru_wasm_fast_tests =
     ~preprocess:(staged_pps [ppx_import; ppx_deriving_show])
 
 let octez_experimental_agnostic_baker_lib =
+  let (PPX {preprocess; preprocessor_deps}) = ppx_profiler in
   public_lib
     "octez-experimental-agnostic-baker-lib"
     ~path:"src/lib_agnostic_baker"
     ~internal_name:"octez_experimental_agnostic_baker"
     ~synopsis:"Octez: library for Agnostic Baker"
+    ~preprocess
+    ~preprocessor_deps
     ~deps:
       [
         octez_rustzcash_deps;
@@ -5358,6 +5361,7 @@ let octez_experimental_agnostic_baker_lib =
         octez_client_base_unix |> open_;
         octez_node_config;
         octez_client_commands |> open_;
+        octez_profiler |> open_;
       ]
 
 (* PROTOCOL PACKAGES *)
diff --git a/opam/octez-experimental-agnostic-baker-lib.opam b/opam/octez-experimental-agnostic-baker-lib.opam
index ee8a3184911c..5ecb396d33b3 100644
--- a/opam/octez-experimental-agnostic-baker-lib.opam
+++ b/opam/octez-experimental-agnostic-baker-lib.opam
@@ -10,9 +10,9 @@ license: "MIT"
 depends: [
   "dune" { >= "3.11.1" }
   "ocaml" { >= "4.14" }
+  "octez-libs" { = version }
   "octez-rustzcash-deps" { = version }
   "bls12-381" { = version }
-  "octez-libs" { = version }
   "octez-shell-libs" { = version }
   "octez-node-config" { = version }
 ]
diff --git a/src/bin_agnostic_baker/main_agnostic_baker.ml b/src/bin_agnostic_baker/main_agnostic_baker.ml
index a1c5132671f8..012833f1d3e0 100644
--- a/src/bin_agnostic_baker/main_agnostic_baker.ml
+++ b/src/bin_agnostic_baker/main_agnostic_baker.ml
@@ -6,6 +6,13 @@
 (*                                                                           *)
 (*****************************************************************************)
 
+let[@warning "-32"] may_start_profiler baking_dir =
+  match Tezos_profiler_unix.Profiler_instance.selected_backend () with
+  | Some {instance_maker; _} ->
+      let profiler_maker = instance_maker ~directory:baking_dir in
+      Agnostic_baker_profiler.init profiler_maker
+  | None -> ()
+
 let run () =
   let open Lwt_result_syntax in
   let Run_args.{node_endpoint; base_dir; baker_args} =
@@ -16,6 +23,7 @@ let run () =
       ~config:(Parameters.log_config ~base_dir)
       ()
   in
+  () [@profiler.overwrite may_start_profiler base_dir] ;
   let daemon = Daemon.create ~node_endpoint ~baker_args in
   let* (_ : unit) = Daemon.run daemon in
   let*! () = Lwt_utils.never_ending () in
diff --git a/src/lib_agnostic_baker/agnostic_baker_profiler.ml b/src/lib_agnostic_baker/agnostic_baker_profiler.ml
new file mode 100644
index 000000000000..9b93ffd25bef
--- /dev/null
+++ b/src/lib_agnostic_baker/agnostic_baker_profiler.ml
@@ -0,0 +1,17 @@
+(*****************************************************************************)
+(*                                                                           *)
+(* SPDX-License-Identifier: MIT                                              *)
+(* Copyright (c) 2025 Trilitech <contact@trili.tech>                         *)
+(*                                                                           *)
+(*****************************************************************************)
+open Profiler
+
+let agnostic_baker_profiler = unplugged ()
+
+let init profiler_maker =
+  match profiler_maker ~name:"agnostic_baker" with
+  | Some instance -> plug agnostic_baker_profiler instance
+  | None -> ()
+
+let create_reset_block_section =
+  section_maker Block_hash.equal Block_hash.to_b58check
diff --git a/src/lib_agnostic_baker/agnostic_baker_profiler.mli b/src/lib_agnostic_baker/agnostic_baker_profiler.mli
new file mode 100644
index 000000000000..3e9e56176b2b
--- /dev/null
+++ b/src/lib_agnostic_baker/agnostic_baker_profiler.mli
@@ -0,0 +1,16 @@
+(*****************************************************************************)
+(*                                                                           *)
+(* SPDX-License-Identifier: MIT                                              *)
+(* Copyright (c) 2025 Trilitech <contact@trili.tech>                         *)
+(*                                                                           *)
+(*****************************************************************************)
+
+(** Unplugged agnostic baker profiler. *)
+val agnostic_baker_profiler : Profiler.profiler
+
+(** Plug the agnostic baker profiler given its name and Profiler instance option. *)
+val init : (name:string -> Profiler.instance option) -> unit
+
+(** Creates a function to reset the block section *)
+val create_reset_block_section :
+  Profiler.profiler -> Block_hash.t * Profiler.metadata -> unit
diff --git a/src/lib_agnostic_baker/daemon.ml b/src/lib_agnostic_baker/daemon.ml
index f396b39727e8..675eaaf0f43b 100644
--- a/src/lib_agnostic_baker/daemon.ml
+++ b/src/lib_agnostic_baker/daemon.ml
@@ -6,6 +6,14 @@
 (*                                                                           *)
 (*****************************************************************************)
 
+module Profiler = struct
+  include (val Profiler.wrap Agnostic_baker_profiler.agnostic_baker_profiler)
+
+  let[@warning "-32"] reset_block_section =
+    Agnostic_baker_profiler.create_reset_block_section
+      Agnostic_baker_profiler.agnostic_baker_profiler
+end
+
 open Agnostic_baker_errors
 
 (* Number of extra levels to keep the old baker alive before shutting it down.
diff --git a/src/lib_agnostic_baker/dune b/src/lib_agnostic_baker/dune
index ba71b4b59cab..266070c8d71e 100644
--- a/src/lib_agnostic_baker/dune
+++ b/src/lib_agnostic_baker/dune
@@ -13,7 +13,10 @@
   octez-libs.base.unix
   octez-shell-libs.client-base-unix
   octez-node-config
-  octez-shell-libs.client-commands)
+  octez-shell-libs.client-commands
+  octez-libs.octez-profiler)
+ (preprocess (pps octez-libs.ppx_profiler))
+ (preprocessor_deps (env_var TEZOS_PPX_PROFILER))
  (flags
   (:standard)
   -open Data_encoding
@@ -21,4 +24,5 @@
   -open Tezos_base
   -open Tezos_base_unix
   -open Tezos_client_base_unix
-  -open Tezos_client_commands))
+  -open Tezos_client_commands
+  -open Tezos_profiler))
-- 
GitLab


From 9ee50eed341990ba4025718572862e52f12286e1 Mon Sep 17 00:00:00 2001
From: Gabriel Moise <gabriel.moise@trili.tech>
Date: Fri, 21 Mar 2025 12:23:20 +0000
Subject: [PATCH 2/6] Agnostic_baker: Initialise agnostic baker profiler

---
 manifest/product_octez.ml                     | 4 ++++
 opam/octez-experimental-agnostic-baker.opam   | 2 +-
 src/bin_agnostic_baker/dune                   | 6 +++++-
 src/bin_agnostic_baker/main_agnostic_baker.ml | 5 +++++
 src/lib_agnostic_baker/daemon.ml              | 9 +++++++++
 src/lib_agnostic_baker/parameters.ml          | 5 -----
 src/lib_agnostic_baker/parameters.mli         | 2 +-
 7 files changed, 25 insertions(+), 8 deletions(-)

diff --git a/manifest/product_octez.ml b/manifest/product_octez.ml
index e3e5e6641269..cff4e1dfa733 100644
--- a/manifest/product_octez.ml
+++ b/manifest/product_octez.ml
@@ -8284,6 +8284,7 @@ let _octez_node =
         ]
 
 let _octez_experimental_agnostic_baker =
+  let (PPX {preprocess; preprocessor_deps}) = ppx_profiler in
   let protocol_deps =
     let deps_for_protocol protocol =
       let is_optional =
@@ -8301,6 +8302,8 @@ let _octez_experimental_agnostic_baker =
     ~path:"src/bin_agnostic_baker"
     ~internal_name:"main_agnostic_baker"
     ~synopsis:"Tezos: `octez-experimental-agnostic-baker` binary for baking"
+    ~preprocess
+    ~preprocessor_deps
     ~release_status:Released
     ~with_macos_security_framework:true
     ~deps:
@@ -8310,6 +8313,7 @@ let _octez_experimental_agnostic_baker =
          octez_base |> open_ ~m:"TzPervasives" |> open_;
          octez_base_unix |> open_;
          octez_experimental_agnostic_baker_lib |> open_;
+         octez_profiler |> open_;
        ]
       @ protocol_deps)
     ~linkall:true
diff --git a/opam/octez-experimental-agnostic-baker.opam b/opam/octez-experimental-agnostic-baker.opam
index bc418220acd1..eab07475ebd5 100644
--- a/opam/octez-experimental-agnostic-baker.opam
+++ b/opam/octez-experimental-agnostic-baker.opam
@@ -10,9 +10,9 @@ license: "MIT"
 depends: [
   "dune" { >= "3.11.1" }
   "ocaml" { >= "4.14" }
+  "octez-libs" { = version }
   "octez-rust-deps" { = version }
   "bls12-381" { = version }
-  "octez-libs" { = version }
   "octez-experimental-agnostic-baker-lib" { = version }
   "octez-protocol-021-PsQuebec-libs" { = version }
   "octez-protocol-022-PsRiotum-libs" { = version }
diff --git a/src/bin_agnostic_baker/dune b/src/bin_agnostic_baker/dune
index d836df1c327c..d184c7a2c707 100644
--- a/src/bin_agnostic_baker/dune
+++ b/src/bin_agnostic_baker/dune
@@ -12,11 +12,14 @@
   octez-libs.base
   octez-libs.base.unix
   octez-experimental-agnostic-baker-lib
+  octez-libs.octez-profiler
   octez-protocol-021-PsQuebec-libs.agnostic-baker
   octez-protocol-022-PsRiotum-libs.agnostic-baker
   (select void_for_linking-octez-protocol-alpha-libs-agnostic-baker from
    (octez-protocol-alpha-libs.agnostic-baker -> void_for_linking-octez-protocol-alpha-libs-agnostic-baker.empty)
    (-> void_for_linking-octez-protocol-alpha-libs-agnostic-baker.empty)))
+ (preprocess (pps octez-libs.ppx_profiler))
+ (preprocessor_deps (env_var TEZOS_PPX_PROFILER))
  (link_flags
   (:standard)
   (:include %{workspace_root}/static-link-flags.sexp)
@@ -27,7 +30,8 @@
   -open Tezos_base.TzPervasives
   -open Tezos_base
   -open Tezos_base_unix
-  -open Octez_experimental_agnostic_baker))
+  -open Octez_experimental_agnostic_baker
+  -open Tezos_profiler))
 
 (rule
  (action
diff --git a/src/bin_agnostic_baker/main_agnostic_baker.ml b/src/bin_agnostic_baker/main_agnostic_baker.ml
index 012833f1d3e0..5dbaafca021b 100644
--- a/src/bin_agnostic_baker/main_agnostic_baker.ml
+++ b/src/bin_agnostic_baker/main_agnostic_baker.ml
@@ -18,6 +18,11 @@ let run () =
   let Run_args.{node_endpoint; base_dir; baker_args} =
     Run_args.parse_args Sys.argv
   in
+  let base_dir =
+    Option.value
+      ~default:Tezos_client_base_unix.Client_config.Cfg_file.default.base_dir
+      base_dir
+  in
   let*! () =
     Tezos_base_unix.Internal_event_unix.init
       ~config:(Parameters.log_config ~base_dir)
diff --git a/src/lib_agnostic_baker/daemon.ml b/src/lib_agnostic_baker/daemon.ml
index 675eaaf0f43b..b693d1d79148 100644
--- a/src/lib_agnostic_baker/daemon.ml
+++ b/src/lib_agnostic_baker/daemon.ml
@@ -171,6 +171,12 @@ let parse_level head_info =
   let json = Ezjsonm.from_string head_info in
   Ezjsonm.find json ["level"] |> Ezjsonm.get_int
 
+(** [parse_block_hash head_info] retrieves the ["hash"] field information from the
+    json information of the chain from [head_info]. *)
+let[@warning "-32"] parse_block_hash head_info =
+  let json = Ezjsonm.from_string head_info in
+  Ezjsonm.find json ["hash"] |> Ezjsonm.get_string |> Block_hash.of_b58check_exn
+
 (** [maybe_kill_old_baker state head_info] checks whether the [old_baker] process
     from the [state] of the agnostic baker has surpassed its lifetime and it stops
     it if that is the case. *)
@@ -201,6 +207,9 @@ let monitor_voting_periods ~state head_stream =
     match head_info_opt with
     | None -> tzfail Lost_node_connection
     | Some head_info ->
+        ()
+        [@profiler.reset_block_section
+          {profiler_module = Profiler} (parse_block_hash head_info)] ;
         let* period_kind, remaining =
           Rpc_services.get_current_period ~node_addr
         in
diff --git a/src/lib_agnostic_baker/parameters.ml b/src/lib_agnostic_baker/parameters.ml
index e273beaa109b..7e67520deb12 100644
--- a/src/lib_agnostic_baker/parameters.ml
+++ b/src/lib_agnostic_baker/parameters.ml
@@ -14,11 +14,6 @@ let default_node_endpoint =
 let default_daily_logs_path = Some "octez-experimental-agnostic-baker"
 
 let log_config ~base_dir =
-  let base_dir : string =
-    match base_dir with
-    | Some p -> p
-    | None -> Tezos_client_base_unix.Client_config.Cfg_file.default.base_dir
-  in
   let daily_logs_path =
     default_daily_logs_path
     |> Option.map Filename.Infix.(fun logdir -> base_dir // "logs" // logdir)
diff --git a/src/lib_agnostic_baker/parameters.mli b/src/lib_agnostic_baker/parameters.mli
index df009a953ce5..79f7c870b154 100644
--- a/src/lib_agnostic_baker/parameters.mli
+++ b/src/lib_agnostic_baker/parameters.mli
@@ -13,7 +13,7 @@ val default_node_endpoint : string
 (** Default logs path for the agnostic baker. *)
 val default_daily_logs_path : string option
 
-val log_config : base_dir:string option -> Tezos_base.Internal_event_config.t
+val log_config : base_dir:string -> Tezos_base.Internal_event_config.t
 
 (** Status of a protocol, based on Manifest/Product_octez/Protocol. A
     protocol is considered as [Active] while it is running on a network,
-- 
GitLab


From 495e4bec6520b6c660c8312a13c8da76047b0b4e Mon Sep 17 00:00:00 2001
From: Gabriel Moise <gabriel.moise@trili.tech>
Date: Fri, 21 Mar 2025 12:30:20 +0000
Subject: [PATCH 3/6] Agnostic_baker: Profile RPC calls and baker process

---
 src/lib_agnostic_baker/daemon.ml | 26 +++++++++++++++++++++-----
 1 file changed, 21 insertions(+), 5 deletions(-)

diff --git a/src/lib_agnostic_baker/daemon.ml b/src/lib_agnostic_baker/daemon.ml
index b693d1d79148..a486bdaeb90a 100644
--- a/src/lib_agnostic_baker/daemon.ml
+++ b/src/lib_agnostic_baker/daemon.ml
@@ -85,7 +85,11 @@ let spawn_baker protocol_hash ~baker_args =
   let baker_args = "./mock-binary" :: baker_args in
   let cancel_promise, canceller = Lwt.wait () in
   let* thread =
-    let*? plugin = Protocol_plugins.proto_plugin_for_protocol protocol_hash in
+    let*? plugin =
+      (Protocol_plugins.proto_plugin_for_protocol
+         protocol_hash
+       [@profiler.record_f {verbosity = Notice} "proto_plugin_for_protocol"])
+    in
     let baker_commands = Commands.baker_commands plugin in
     return
     @@ run_thread
@@ -190,7 +194,9 @@ let maybe_kill_old_baker state head_info =
         let* () =
           Agnostic_baker_events.(emit stopping_baker) baker.protocol_hash
         in
-        Lwt.wakeup baker.process.canceller 0 ;
+        Lwt.wakeup
+          baker.process.canceller
+          0 [@profiler.record_f {verbosity = Notice} "kill old baker"] ;
         state.old_baker <- None ;
         return_unit)
       else return_unit
@@ -211,14 +217,23 @@ let monitor_voting_periods ~state head_stream =
         [@profiler.reset_block_section
           {profiler_module = Profiler} (parse_block_hash head_info)] ;
         let* period_kind, remaining =
-          Rpc_services.get_current_period ~node_addr
+          (Rpc_services.get_current_period
+             ~node_addr
+           [@profiler.record_s {verbosity = Notice} "get_current_period"])
         in
         let*! () =
           Agnostic_baker_events.(emit period_status) (period_kind, remaining)
         in
-        let*! () = maybe_kill_old_baker state head_info in
+        let*! () =
+          (maybe_kill_old_baker
+             state
+             head_info
+           [@profiler.record_s {verbosity = Notice} "maybe_kill_old_baker"])
+        in
         let* next_protocol_hash =
-          Rpc_services.get_next_protocol_hash ~node_addr
+          (Rpc_services.get_next_protocol_hash
+             ~node_addr
+           [@profiler.record_s {verbosity = Notice} "get_next_protocol_hash"])
         in
         let* current_protocol_hash =
           match state.current_baker with
@@ -234,6 +249,7 @@ let monitor_voting_periods ~state head_stream =
               ~next_protocol_hash
               ~level_to_kill_old_baker:
                 (parse_level head_info + extra_levels_for_old_baker)
+            [@profiler.record_s {verbosity = Notice} "hot_swap_baker"]
           else return_unit
         in
         loop ()
-- 
GitLab


From 9efaae182595ca231cf8183747a6e42309fdcd88 Mon Sep 17 00:00:00 2001
From: Gabriel Moise <gabriel.moise@trili.tech>
Date: Mon, 3 Mar 2025 16:47:17 +0000
Subject: [PATCH 4/6] Agnostic_baker: Make printing of longer messages work
 properly

---
 src/lib_agnostic_baker/agnostic_baker_events.ml | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/lib_agnostic_baker/agnostic_baker_events.ml b/src/lib_agnostic_baker/agnostic_baker_events.ml
index 4a591d8ffb79..c58e8db584cc 100644
--- a/src/lib_agnostic_baker/agnostic_baker_events.ml
+++ b/src/lib_agnostic_baker/agnostic_baker_events.ml
@@ -22,6 +22,7 @@ let starting_baker =
     ("proto", Protocol_hash.encoding)
     ("args", string)
     ~pp1:Protocol_hash.pp_short
+    ~pp2:Format.pp_print_string
 
 let baker_running =
   declare_1
-- 
GitLab


From dda37062f7172f4a858eed316a08cc0f007f5a2a Mon Sep 17 00:00:00 2001
From: Gabriel Moise <gabriel.moise@trili.tech>
Date: Fri, 21 Mar 2025 12:32:18 +0000
Subject: [PATCH 5/6] Agnostic_baker: Improve documentation

---
 src/lib_agnostic_baker/daemon.ml | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/lib_agnostic_baker/daemon.ml b/src/lib_agnostic_baker/daemon.ml
index a486bdaeb90a..5ac613b5d1bd 100644
--- a/src/lib_agnostic_baker/daemon.ml
+++ b/src/lib_agnostic_baker/daemon.ml
@@ -204,7 +204,8 @@ let maybe_kill_old_baker state head_info =
 (** [monitor_voting_periods ~state head_stream] continuously monitors [heads_stream]
     to detect protocol changes. It will:
     - Shut down an old baker it its time has come;
-    - Spawn and "hot-swap" to a new baker if the next protocol hash is different. *)
+    - Spawn and "hot-swap" to a new baker if the next protocol hash is different. 
+    The voting period information is used for logging purposes. *)
 let monitor_voting_periods ~state head_stream =
   let open Lwt_result_syntax in
   let node_addr = state.node_endpoint in
-- 
GitLab


From ec99e7c90a6c8b48b7ef592ac82562ace2f280d2 Mon Sep 17 00:00:00 2001
From: Gabriel Moise <gabriel.moise@trili.tech>
Date: Fri, 21 Mar 2025 13:48:33 +0000
Subject: [PATCH 6/6] Agnostic_baker: Use Rpc_services functions for level and
 block hash

---
 .../agnostic_baker_events.ml                  |  7 +-
 src/lib_agnostic_baker/daemon.ml              | 64 +++++++++----------
 src/lib_agnostic_baker/rpc_services.ml        | 19 ++++++
 src/lib_agnostic_baker/rpc_services.mli       |  4 ++
 4 files changed, 60 insertions(+), 34 deletions(-)

diff --git a/src/lib_agnostic_baker/agnostic_baker_events.ml b/src/lib_agnostic_baker/agnostic_baker_events.ml
index c58e8db584cc..ce6a651baadc 100644
--- a/src/lib_agnostic_baker/agnostic_baker_events.ml
+++ b/src/lib_agnostic_baker/agnostic_baker_events.ml
@@ -93,12 +93,15 @@ let waiting_for_active_protocol =
     ()
 
 let period_status =
-  declare_2
+  declare_3
     ~section
     ~alternative_color
     ~level:Notice
     ~name:"period_status"
-    ~msg:"new block on {period} period (remaining period duration {remaining})"
+    ~msg:
+      "new block ({block}) on {period} period (remaining period duration \
+       {remaining})"
+    ("block", Block_hash.encoding)
     ("period", string)
     ("remaining", int31)
 
diff --git a/src/lib_agnostic_baker/daemon.ml b/src/lib_agnostic_baker/daemon.ml
index 5ac613b5d1bd..0dfe075731dc 100644
--- a/src/lib_agnostic_baker/daemon.ml
+++ b/src/lib_agnostic_baker/daemon.ml
@@ -169,29 +169,20 @@ let hot_swap_baker ~state ~current_protocol_hash ~next_protocol_hash
   state.current_baker <- Some new_baker ;
   return_unit
 
-(** [parse_level head_info] retrieves the ["level"] field information from the
-    json information of the chain from [head_info]. *)
-let parse_level head_info =
-  let json = Ezjsonm.from_string head_info in
-  Ezjsonm.find json ["level"] |> Ezjsonm.get_int
-
-(** [parse_block_hash head_info] retrieves the ["hash"] field information from the
-    json information of the chain from [head_info]. *)
-let[@warning "-32"] parse_block_hash head_info =
-  let json = Ezjsonm.from_string head_info in
-  Ezjsonm.find json ["hash"] |> Ezjsonm.get_string |> Block_hash.of_b58check_exn
-
-(** [maybe_kill_old_baker state head_info] checks whether the [old_baker] process
+(** [maybe_kill_old_baker state node_addr] checks whether the [old_baker] process
     from the [state] of the agnostic baker has surpassed its lifetime and it stops
     it if that is the case. *)
-let maybe_kill_old_baker state head_info =
-  let open Lwt_syntax in
+let maybe_kill_old_baker state node_addr =
+  let open Lwt_result_syntax in
   match state.old_baker with
   | None -> return_unit
   | Some {baker; level_to_kill} ->
-      let head_level = parse_level head_info in
+      let* head_level =
+        (Rpc_services.get_level
+           ~node_addr [@profiler.record_s {verbosity = Notice} "get_level"])
+      in
       if head_level >= level_to_kill then (
-        let* () =
+        let*! () =
           Agnostic_baker_events.(emit stopping_baker) baker.protocol_hash
         in
         Lwt.wakeup
@@ -210,25 +201,30 @@ let monitor_voting_periods ~state head_stream =
   let open Lwt_result_syntax in
   let node_addr = state.node_endpoint in
   let rec loop () =
-    let*! head_info_opt = Lwt_stream.get head_stream in
-    match head_info_opt with
+    let*! v = Lwt_stream.get head_stream in
+    match v with
     | None -> tzfail Lost_node_connection
-    | Some head_info ->
+    | Some _tick ->
+        let* block_hash =
+          (Rpc_services.get_block_hash
+             ~node_addr
+           [@profiler.record_s {verbosity = Notice} "get_block_hash"])
+        in
         ()
-        [@profiler.reset_block_section
-          {profiler_module = Profiler} (parse_block_hash head_info)] ;
+        [@profiler.reset_block_section {profiler_module = Profiler} block_hash] ;
         let* period_kind, remaining =
           (Rpc_services.get_current_period
              ~node_addr
            [@profiler.record_s {verbosity = Notice} "get_current_period"])
         in
         let*! () =
-          Agnostic_baker_events.(emit period_status) (period_kind, remaining)
+          Agnostic_baker_events.(emit period_status)
+            (block_hash, period_kind, remaining)
         in
-        let*! () =
+        let* () =
           (maybe_kill_old_baker
              state
-             head_info
+             node_addr
            [@profiler.record_s {verbosity = Notice} "maybe_kill_old_baker"])
         in
         let* next_protocol_hash =
@@ -244,13 +240,17 @@ let monitor_voting_periods ~state head_stream =
         let* () =
           if not (Protocol_hash.equal current_protocol_hash next_protocol_hash)
           then
-            hot_swap_baker
-              ~state
-              ~current_protocol_hash
-              ~next_protocol_hash
-              ~level_to_kill_old_baker:
-                (parse_level head_info + extra_levels_for_old_baker)
-            [@profiler.record_s {verbosity = Notice} "hot_swap_baker"]
+            let* head_level =
+              (Rpc_services.get_level
+                 ~node_addr
+               [@profiler.record_s {verbosity = Notice} "get_level"])
+            in
+            (hot_swap_baker
+               ~state
+               ~current_protocol_hash
+               ~next_protocol_hash
+               ~level_to_kill_old_baker:(head_level + extra_levels_for_old_baker)
+             [@profiler.record_s {verbosity = Notice} "hot_swap_baker"])
           else return_unit
         in
         loop ()
diff --git a/src/lib_agnostic_baker/rpc_services.ml b/src/lib_agnostic_baker/rpc_services.ml
index bde5622bb778..c2415fc5cbc1 100644
--- a/src/lib_agnostic_baker/rpc_services.ml
+++ b/src/lib_agnostic_baker/rpc_services.ml
@@ -64,6 +64,25 @@ let get_level ~node_addr =
   in
   call_and_wrap_rpc ~node_addr ~uri ~f
 
+let get_block_hash ~node_addr =
+  let open Lwt_result_syntax in
+  let f json =
+    (* Hash field in the RPC result *)
+    let name = "hash" in
+    let* v =
+      match json with
+      | `O fields -> (
+          match List.assoc_opt ~equal:( = ) name fields with
+          | None -> tzfail (Cannot_decode_node_data ("missing field " ^ name))
+          | Some node -> return node)
+      | _ -> tzfail (Cannot_decode_node_data "not an object")
+    in
+    let block_hash = Block_hash.of_b58check_exn @@ Ezjsonm.get_string v in
+    return block_hash
+  in
+  let uri = Format.sprintf "%s/chains/main/blocks/head/header" node_addr in
+  call_and_wrap_rpc ~node_addr ~uri ~f
+
 let get_next_protocol_hash ~node_addr =
   let open Lwt_result_syntax in
   let f json =
diff --git a/src/lib_agnostic_baker/rpc_services.mli b/src/lib_agnostic_baker/rpc_services.mli
index 063adf0e11f0..904ac48456d9 100644
--- a/src/lib_agnostic_baker/rpc_services.mli
+++ b/src/lib_agnostic_baker/rpc_services.mli
@@ -16,6 +16,10 @@ val request_uri :
 (** [get_level ~node_addr] returns the level of the block. *)
 val get_level : node_addr:string -> (int, error trace) result Lwt.t
 
+(** [get_level ~node_addr] returns the hash of the block. *)
+val get_block_hash :
+  node_addr:string -> (Block_hash.t, error trace) result Lwt.t
+
 (** [get_next_protocol_hash ~node_addr] returns the protocol hash
     contained in the [next_protocol] field of the metadata of a
     block. *)
-- 
GitLab