From cf8555bcec0483cf5f39c3a9c096f4161477092a Mon Sep 17 00:00:00 2001
From: Simon Cruanes <simon.cruanes.2007@m4x.org>
Date: Wed, 14 Feb 2024 21:05:35 -0500
Subject: [PATCH] revert: remove name on futures and tasks

async tracing will be more robust, and is enabled by
task local storage
---
 benchs/fib_rec.ml                 |  8 ++---
 benchs/pi.ml                      |  2 +-
 src/core/fifo_pool.ml             | 14 ++++----
 src/core/fut.ml                   | 59 +++++++++++++------------------
 src/core/fut.mli                  | 13 +++----
 src/core/immediate_runner.ml      |  5 +--
 src/core/moonpool.mli             | 26 +++-----------
 src/core/runner.ml                | 12 +++----
 src/core/runner.mli               | 11 ++----
 src/core/suspend_.ml              |  5 ++-
 src/core/suspend_.mli             |  6 ++--
 src/core/ws_pool.ml               | 37 +++++++------------
 src/fib/fiber.ml                  | 12 +++----
 src/fib/fiber.mli                 |  4 +--
 src/forkjoin/moonpool_forkjoin.ml |  2 +-
 test/effect-based/t_fib1.ml       |  2 +-
 16 files changed, 80 insertions(+), 138 deletions(-)

diff --git a/benchs/fib_rec.ml b/benchs/fib_rec.ml
index 66eded93..82d588cf 100644
--- a/benchs/fib_rec.ml
+++ b/benchs/fib_rec.ml
@@ -14,7 +14,7 @@ let cutoff = ref 20
 
 let rec fib ~on x : int Fut.t =
   if x <= !cutoff then
-    Fut.spawn ~name:"fib" ~on (fun () -> fib_direct x)
+    Fut.spawn ~on (fun () -> fib_direct x)
   else
     let open Fut.Infix in
     let+ t1 = fib ~on (x - 1) and+ t2 = fib ~on (x - 2) in
@@ -31,14 +31,14 @@ let fib_fj ~on x : int Fut.t =
       n1 + n2
     )
   in
-  Fut.spawn ~name:"fib" ~on (fun () -> fib_rec x)
+  Fut.spawn ~on (fun () -> fib_rec x)
 
 let fib_await ~on x : int Fut.t =
   let rec fib_rec x : int Fut.t =
     if x <= !cutoff then
-      Fut.spawn ~name:"fib" ~on (fun () -> fib_direct x)
+      Fut.spawn ~on (fun () -> fib_direct x)
     else
-      Fut.spawn ~name:"fib" ~on (fun () ->
+      Fut.spawn ~on (fun () ->
           let n1 = fib_rec (x - 1) in
           let n2 = fib_rec (x - 2) in
           let n1 = Fut.await n1 in
diff --git a/benchs/pi.ml b/benchs/pi.ml
index 4eae7eb0..63ddc2ca 100644
--- a/benchs/pi.ml
+++ b/benchs/pi.ml
@@ -76,7 +76,7 @@ let run_fork_join ~kind num_steps : float =
   let step = 1. /. float num_steps in
   let global_sum = Lock.create 0. in
 
-  Ws_pool.run_wait_block ~name:"pi.fj" pool (fun () ->
+  Ws_pool.run_wait_block pool (fun () ->
       FJ.for_
         ~chunk_size:(3 + (num_steps / num_tasks))
         num_steps
diff --git a/src/core/fifo_pool.ml b/src/core/fifo_pool.ml
index d2757324..58177b3f 100644
--- a/src/core/fifo_pool.ml
+++ b/src/core/fifo_pool.ml
@@ -6,7 +6,6 @@ let k_storage = Task_local_storage.Private_.Storage.k_storage
 
 type task_full = {
   f: unit -> unit;
-  name: string;
   ls: Task_local_storage.storage;
 }
 
@@ -44,18 +43,17 @@ let worker_thread_ (self : state) (runner : t) ~on_exn ~around_task : unit =
     !cur_ls
   in
 
-  let run_another_task ls ~name task' =
+  let run_another_task ls task' =
     let ls' = Task_local_storage.Private_.Storage.copy ls in
-    schedule_ self { f = task'; name; ls = ls' }
+    schedule_ self { f = task'; ls = ls' }
   in
 
   let run_task (task : task_full) : unit =
     cur_ls := task.ls;
     let _ctx = before_task runner in
-    cur_span := Tracing_.enter_span task.name;
 
     let resume ls k res =
-      schedule_ self { f = (fun () -> k res); name = task.name; ls }
+      schedule_ self { f = (fun () -> k res);  ls }
     in
 
     (* run the task now, catching errors, handling effects *)
@@ -105,12 +103,12 @@ type ('a, 'b) create_args =
   ?on_exn:(exn -> Printexc.raw_backtrace -> unit) ->
   ?around_task:(t -> 'b) * (t -> 'b -> unit) ->
   ?num_threads:int ->
-  ?name:string ->
+    ?name:string ->
   'a
 
 let create ?(on_init_thread = default_thread_init_exit_)
     ?(on_exit_thread = default_thread_init_exit_) ?(on_exn = fun _ _ -> ())
-    ?around_task ?num_threads ?name () : t =
+    ?around_task ?num_threads  ?name () : t =
   (* wrapper *)
   let around_task =
     match around_task with
@@ -131,7 +129,7 @@ let create ?(on_init_thread = default_thread_init_exit_)
     { threads = Array.make num_threads dummy; q = Bb_queue.create () }
   in
 
-  let run_async ~name ~ls f = schedule_ pool { f; name; ls } in
+  let run_async ~ls f = schedule_ pool { f; ls } in
 
   let runner =
     Runner.For_runner_implementors.create
diff --git a/src/core/fut.ml b/src/core/fut.ml
index 2c7d6896..5cbcb366 100644
--- a/src/core/fut.ml
+++ b/src/core/fut.ml
@@ -5,21 +5,13 @@ type 'a waiter = 'a or_error -> unit
 
 type 'a state =
   | Done of 'a or_error
-  | Waiting of {
-      waiters: 'a waiter list;
-      name: string;
-    }
+  | Waiting of { waiters: 'a waiter list }
 
 type 'a t = { st: 'a state A.t } [@@unboxed]
 type 'a promise = 'a t
 
-let[@inline] get_name_ (self : _ t) =
-  match A.get self.st with
-  | Done _ -> ""
-  | Waiting { name; _ } -> name
-
-let make ?(name = "") () =
-  let fut = { st = A.make (Waiting { waiters = []; name }) } in
+let make () =
+  let fut = { st = A.make (Waiting { waiters = [] }) } in
   fut, fut
 
 let[@inline] of_result x : _ t = { st = A.make (Done x) }
@@ -72,8 +64,8 @@ let on_result (self : _ t) (f : _ waiter) : unit =
     | Done x ->
       f x;
       false
-    | Waiting { waiters = l; name } ->
-      not (A.compare_and_set self.st st (Waiting { waiters = f :: l; name }))
+    | Waiting { waiters = l } ->
+      not (A.compare_and_set self.st st (Waiting { waiters = f :: l }))
   do
     Domain_.relax ()
   done
@@ -86,7 +78,7 @@ let fulfill (self : _ t) (r : _ result) : unit =
     let st = A.get self.st in
     match st with
     | Done _ -> raise Already_fulfilled
-    | Waiting { waiters = l; name = _ } ->
+    | Waiting { waiters = l } ->
       let did_swap = A.compare_and_set self.st st (Done r) in
       if did_swap then (
         (* success, now call all the waiters *)
@@ -105,7 +97,7 @@ let[@inline] fulfill_idempotent self r =
 
 (* ### combinators ### *)
 
-let spawn ?name ?ls ~on f : _ t =
+let spawn ?ls ~on f : _ t =
   let fut, promise = make () in
 
   let task () =
@@ -118,13 +110,13 @@ let spawn ?name ?ls ~on f : _ t =
     fulfill promise res
   in
 
-  Runner.run_async ?name ?ls on task;
+  Runner.run_async ?ls on task;
   fut
 
-let spawn_on_current_runner ?name ?ls f : _ t =
+let spawn_on_current_runner ?ls f : _ t =
   match Runner.get_current_runner () with
   | None -> failwith "Fut.spawn_on_current_runner: not running on a runner"
-  | Some on -> spawn ?name ?ls ~on f
+  | Some on -> spawn ?ls ~on f
 
 let reify_error (f : 'a t) : 'a or_error t =
   match peek f with
@@ -150,22 +142,20 @@ let map ?on ~f fut : _ t =
     | Error e_bt -> Error e_bt
   in
 
-  let name = get_name_ fut in
   match peek fut, get_runner_ ?on () with
   | Some res, None -> of_result @@ map_immediate_ res
   | Some res, Some runner ->
-    let fut2, promise = make ~name () in
-    Runner.run_async ~name runner (fun () ->
-        fulfill promise @@ map_immediate_ res);
+    let fut2, promise = make () in
+    Runner.run_async runner (fun () -> fulfill promise @@ map_immediate_ res);
     fut2
   | None, None ->
-    let fut2, promise = make ~name () in
+    let fut2, promise = make () in
     on_result fut (fun res -> fulfill promise @@ map_immediate_ res);
     fut2
   | None, Some runner ->
-    let fut2, promise = make ~name () in
+    let fut2, promise = make () in
     on_result fut (fun res ->
-        Runner.run_async ~name runner (fun () ->
+        Runner.run_async runner (fun () ->
             fulfill promise @@ map_immediate_ res));
     fut2
 
@@ -174,7 +164,7 @@ let join (fut : 'a t t) : 'a t =
   | Some (Ok f) -> f
   | Some (Error (e, bt)) -> fail e bt
   | None ->
-    let fut2, promise = make ~name:(get_name_ fut) () in
+    let fut2, promise = make () in
     on_result fut (function
       | Ok sub_fut -> on_result sub_fut (fulfill promise)
       | Error _ as e -> fulfill promise e);
@@ -197,20 +187,19 @@ let bind ?on ~f fut : _ t =
     on_result f_res_fut (fun r -> fulfill promise r)
   in
 
-  let name = get_name_ fut in
   match peek fut, get_runner_ ?on () with
   | Some res, Some runner ->
-    let fut2, promise = make ~name () in
-    Runner.run_async ~name runner (bind_and_fulfill res promise);
+    let fut2, promise = make () in
+    Runner.run_async runner (bind_and_fulfill res promise);
     fut2
   | Some res, None -> apply_f_to_res res
   | None, Some runner ->
-    let fut2, promise = make ~name () in
+    let fut2, promise = make () in
     on_result fut (fun r ->
-        Runner.run_async ~name runner (bind_and_fulfill r promise));
+        Runner.run_async runner (bind_and_fulfill r promise));
     fut2
   | None, None ->
-    let fut2, promise = make ~name () in
+    let fut2, promise = make () in
     on_result fut (fun res -> bind_and_fulfill res promise ());
     fut2
 
@@ -234,7 +223,7 @@ let both a b : _ t =
   | Some (Ok x), Some (Ok y) -> return (x, y)
   | Some (Error (e, bt)), _ | _, Some (Error (e, bt)) -> fail e bt
   | _ ->
-    let fut, promise = make ~name:(get_name_ a) () in
+    let fut, promise = make () in
 
     let st = A.make `Neither in
     on_result a (function
@@ -267,7 +256,7 @@ let choose a b : _ t =
   | _, Some (Ok y) -> return (Either.Right y)
   | Some (Error (e, bt)), Some (Error _) -> fail e bt
   | _ ->
-    let fut, promise = make ~name:(get_name_ a) () in
+    let fut, promise = make () in
 
     let one_failure = A.make false in
     on_result a (function
@@ -290,7 +279,7 @@ let choose_same a b : _ t =
   | _, Some (Ok y) -> return y
   | Some (Error (e, bt)), Some (Error _) -> fail e bt
   | _ ->
-    let fut, promise = make ~name:(get_name_ a) () in
+    let fut, promise = make () in
 
     let one_failure = A.make false in
     on_result a (function
diff --git a/src/core/fut.mli b/src/core/fut.mli
index a82975f3..7c0d4466 100644
--- a/src/core/fut.mli
+++ b/src/core/fut.mli
@@ -26,9 +26,8 @@ type 'a promise
 (** A promise, which can be fulfilled exactly once to set
       the corresponding future *)
 
-val make : ?name:string -> unit -> 'a t * 'a promise
-(** Make a new future with the associated promise.
-    @param name name for the future, used for tracing. since NEXT_RELEASE. *)
+val make : unit -> 'a t * 'a promise
+(** Make a new future with the associated promise. *)
 
 val on_result : 'a t -> ('a or_error -> unit) -> unit
 (** [on_result fut f] registers [f] to be called in the future
@@ -95,16 +94,12 @@ val is_failed : _ t -> bool
 (** {2 Combinators} *)
 
 val spawn :
-  ?name:string ->
-  ?ls:Task_local_storage.storage ->
-  on:Runner.t ->
-  (unit -> 'a) ->
-  'a t
+  ?ls:Task_local_storage.storage -> on:Runner.t -> (unit -> 'a) -> 'a t
 (** [spaw ~on f] runs [f()] on the given runner [on], and return a future that will
       hold its result. *)
 
 val spawn_on_current_runner :
-  ?name:string -> ?ls:Task_local_storage.storage -> (unit -> 'a) -> 'a t
+  ?ls:Task_local_storage.storage -> (unit -> 'a) -> 'a t
 (** This must be run from inside a runner, and schedules
     the new task on it as well.
 
diff --git a/src/core/immediate_runner.ml b/src/core/immediate_runner.ml
index c260f439..9412fd35 100644
--- a/src/core/immediate_runner.ml
+++ b/src/core/immediate_runner.ml
@@ -4,19 +4,16 @@ include Runner
 (* convenient alias *)
 let k_ls = Task_local_storage.Private_.Storage.k_storage
 
-let run_async_ ~name ~ls f =
+let run_async_ ~ls f =
   let cur_ls = ref ls in
   TLS.set k_ls (Some cur_ls);
   cur_ls := ls;
-  let sp = Tracing_.enter_span name in
   try
     let x = f () in
-    Tracing_.exit_span sp;
     TLS.set k_ls None;
     x
   with e ->
     let bt = Printexc.get_raw_backtrace () in
-    Tracing_.exit_span sp;
     TLS.set k_ls None;
     Printexc.raise_with_backtrace e bt
 
diff --git a/src/core/moonpool.mli b/src/core/moonpool.mli
index 23ee52d8..c8049503 100644
--- a/src/core/moonpool.mli
+++ b/src/core/moonpool.mli
@@ -26,25 +26,14 @@ val start_thread_on_some_domain : ('a -> unit) -> 'a -> Thread.t
     to run all the various threads needed in an application (timers, event loops, etc.) *)
 
 val run_async :
-  ?name:string ->
-  ?ls:Task_local_storage.storage ->
-  Runner.t ->
-  (unit -> unit) ->
-  unit
+  ?ls:Task_local_storage.storage -> Runner.t -> (unit -> unit) -> unit
 (** [run_async runner task] schedules the task to run
   on the given runner. This means [task()] will be executed
   at some point in the future, possibly in another thread.
-  @param name if provided and [Trace] is present in dependencies, a span
-    will be created when the task starts, and will stop when the task is over.
-    (since NEXT_RELEASE)
   @since 0.5 *)
 
 val run_wait_block :
-  ?name:string ->
-  ?ls:Task_local_storage.storage ->
-  Runner.t ->
-  (unit -> 'a) ->
-  'a
+  ?ls:Task_local_storage.storage -> Runner.t -> (unit -> 'a) -> 'a
 (** [run_wait_block runner f] schedules [f] for later execution
     on the runner, like {!run_async}.
     It then blocks the current thread until [f()] is done executing,
@@ -63,21 +52,14 @@ val recommended_thread_count : unit -> int
   @since 0.5 *)
 
 val spawn :
-  ?name:string ->
-  ?ls:Task_local_storage.storage ->
-  on:Runner.t ->
-  (unit -> 'a) ->
-  'a Fut.t
+  ?ls:Task_local_storage.storage -> on:Runner.t -> (unit -> 'a) -> 'a Fut.t
 (** [spawn ~on f] runs [f()] on the runner (a thread pool typically)
     and returns a future result for it. See {!Fut.spawn}.
-    @param name if provided and [Trace] is present in dependencies,
-      a span will be created for the future. (since 0.6)
     @since 0.5 *)
 
 val spawn_on_current_runner :
-  ?name:string -> ?ls:Task_local_storage.storage -> (unit -> 'a) -> 'a Fut.t
+  ?ls:Task_local_storage.storage -> (unit -> 'a) -> 'a Fut.t
 (** See {!Fut.spawn_on_current_runner}.
-    @param name see {!spawn}. since 0.6.
     @since 0.5 *)
 
 [@@@ifge 5.0]
diff --git a/src/core/runner.ml b/src/core/runner.ml
index 207ea56d..360ec6ba 100644
--- a/src/core/runner.ml
+++ b/src/core/runner.ml
@@ -3,7 +3,7 @@ module TLS = Thread_local_storage_
 type task = unit -> unit
 
 type t = {
-  run_async: name:string -> ls:Task_local_storage.storage -> task -> unit;
+  run_async: ls:Task_local_storage.storage -> task -> unit;
   shutdown: wait:bool -> unit -> unit;
   size: unit -> int;
   num_tasks: unit -> int;
@@ -11,9 +11,9 @@ type t = {
 
 exception Shutdown
 
-let[@inline] run_async ?(name = "")
-    ?(ls = Task_local_storage.Private_.Storage.create ()) (self : t) f : unit =
-  self.run_async ~name ~ls f
+let[@inline] run_async ?(ls = Task_local_storage.Private_.Storage.create ())
+    (self : t) f : unit =
+  self.run_async ~ls f
 
 let[@inline] shutdown (self : t) : unit = self.shutdown ~wait:true ()
 
@@ -23,9 +23,9 @@ let[@inline] shutdown_without_waiting (self : t) : unit =
 let[@inline] num_tasks (self : t) : int = self.num_tasks ()
 let[@inline] size (self : t) : int = self.size ()
 
-let run_wait_block ?name ?ls self (f : unit -> 'a) : 'a =
+let run_wait_block ?ls self (f : unit -> 'a) : 'a =
   let q = Bb_queue.create () in
-  run_async ?name ?ls self (fun () ->
+  run_async ?ls self (fun () ->
       try
         let x = f () in
         Bb_queue.push q (Ok x)
diff --git a/src/core/runner.mli b/src/core/runner.mli
index 5b937c09..331e8b50 100644
--- a/src/core/runner.mli
+++ b/src/core/runner.mli
@@ -33,19 +33,14 @@ val shutdown_without_waiting : t -> unit
 
 exception Shutdown
 
-val run_async :
-  ?name:string -> ?ls:Task_local_storage.storage -> t -> task -> unit
+val run_async : ?ls:Task_local_storage.storage -> t -> task -> unit
 (** [run_async pool f] schedules [f] for later execution on the runner
     in one of the threads. [f()] will run on one of the runner's
     worker threads/domains.
-    @param name if provided and [Trace] is present in dependencies, a span
-    will be created when the task starts, and will stop when the task is over.
-    (since NEXT_RELEASE)
     @param ls if provided, run the task with this initial local storage
     @raise Shutdown if the runner was shut down before [run_async] was called. *)
 
-val run_wait_block :
-  ?name:string -> ?ls:Task_local_storage.storage -> t -> (unit -> 'a) -> 'a
+val run_wait_block : ?ls:Task_local_storage.storage -> t -> (unit -> 'a) -> 'a
 (** [run_wait_block pool f] schedules [f] for later execution
     on the pool, like {!run_async}.
     It then blocks the current thread until [f()] is done executing,
@@ -65,7 +60,7 @@ module For_runner_implementors : sig
     size:(unit -> int) ->
     num_tasks:(unit -> int) ->
     shutdown:(wait:bool -> unit -> unit) ->
-    run_async:(name:string -> ls:Task_local_storage.storage -> task -> unit) ->
+    run_async:(ls:Task_local_storage.storage -> task -> unit) ->
     unit ->
     t
   (** Create a new runner.
diff --git a/src/core/suspend_.ml b/src/core/suspend_.ml
index 4d15ac77..cdd680a5 100644
--- a/src/core/suspend_.ml
+++ b/src/core/suspend_.ml
@@ -7,7 +7,7 @@ type task = unit -> unit
 
 type suspension_handler = {
   handle:
-    run:(name:string -> task -> unit) ->
+    run:(task -> unit) ->
     resume:(suspension -> unit Exn_bt.result -> unit) ->
     suspension ->
     unit;
@@ -27,8 +27,7 @@ type with_suspend_handler =
   | WSH : {
       on_suspend: unit -> 'state;
           (** on_suspend called when [f()] suspends itself. *)
-      run: 'state -> name:string -> task -> unit;
-          (** run used to schedule new tasks *)
+      run: 'state -> task -> unit;  (** run used to schedule new tasks *)
       resume: 'state -> suspension -> unit Exn_bt.result -> unit;
           (** resume run the suspension. Must be called exactly once. *)
     }
diff --git a/src/core/suspend_.mli b/src/core/suspend_.mli
index 1fff43ac..bd8a9a9d 100644
--- a/src/core/suspend_.mli
+++ b/src/core/suspend_.mli
@@ -14,7 +14,7 @@ type task = unit -> unit
 
 type suspension_handler = {
   handle:
-    run:(name:string -> task -> unit) ->
+    run:(task -> unit) ->
     resume:(suspension -> unit Exn_bt.result -> unit) ->
     suspension ->
     unit;
@@ -24,7 +24,6 @@ type suspension_handler = {
 
    The handler is given a few things:
 
-   - the name (if any) of the current computation
    - the suspended computation (which can be resumed with a result
      eventually);
    - a [run] function that can be used to start tasks to perform some
@@ -70,8 +69,7 @@ type with_suspend_handler =
   | WSH : {
       on_suspend: unit -> 'state;
           (** on_suspend called when [f()] suspends itself. *)
-      run: 'state -> name:string -> task -> unit;
-          (** run used to schedule new tasks *)
+      run: 'state -> task -> unit;  (** run used to schedule new tasks *)
       resume: 'state -> suspension -> unit Exn_bt.result -> unit;
           (** resume run the suspension. Must be called exactly once. *)
     }
diff --git a/src/core/ws_pool.ml b/src/core/ws_pool.ml
index d1fd7cf3..5627a4bb 100644
--- a/src/core/ws_pool.ml
+++ b/src/core/ws_pool.ml
@@ -16,7 +16,6 @@ end
 
 type task_full = {
   f: task;
-  name: string;
   ls: Task_local_storage.storage;
 }
 
@@ -26,7 +25,6 @@ type worker_state = {
   pool_id_: Id.t;  (** Unique per pool *)
   mutable thread: Thread.t;
   q: task_full WSQ.t;  (** Work stealing queue *)
-  mutable cur_span: int64;
   cur_ls: Task_local_storage.storage ref;  (** Task storage *)
   rng: Random.State.t;
 }
@@ -75,10 +73,10 @@ let[@inline] try_wake_someone_ (self : state) : unit =
   )
 
 (** Run [task] as is, on the pool. *)
-let schedule_task_ (self : state) ~name ~ls (w : worker_state option) (f : task)
+let schedule_task_ (self : state) ~ls (w : worker_state option) (f : task)
     : unit =
   (* Printf.printf "schedule task now (%d)\n%!" (Thread.id @@ Thread.self ()); *)
-  let task = { f; name; ls } in
+  let task = { f; ls } in
   match w with
   | Some w when Id.equal self.id_ w.pool_id_ ->
     (* we're on this same pool, schedule in the worker's state. Otherwise
@@ -107,33 +105,26 @@ let schedule_task_ (self : state) ~name ~ls (w : worker_state option) (f : task)
       raise Shutdown
 
 (** Run this task, now. Must be called from a worker. *)
-let run_task_now_ (self : state) ~runner (w : worker_state) ~name ~ls task :
+let run_task_now_ (self : state) ~runner (w : worker_state) ~ls task :
     unit =
   (* Printf.printf "run task now (%d)\n%!" (Thread.id @@ Thread.self ()); *)
   let (AT_pair (before_task, after_task)) = self.around_task in
   w.cur_ls := ls;
   let _ctx = before_task runner in
 
-  w.cur_span <- Tracing_.enter_span name;
-  let[@inline] exit_span_ () =
-    Tracing_.exit_span w.cur_span;
-    w.cur_span <- Tracing_.dummy_span
-  in
-
-  let on_suspend () =
-    exit_span_ ();
+  let[@inline] on_suspend () =
     !(w.cur_ls)
   in
 
-  let run_another_task ls ~name task' =
+  let run_another_task ls task' =
     let w = find_current_worker_ () in
     let ls' = Task_local_storage.Private_.Storage.copy ls in
-    schedule_task_ self w ~name ~ls:ls' task'
+    schedule_task_ self w ~ls:ls' task'
   in
 
   let resume ls k r =
     let w = find_current_worker_ () in
-    schedule_task_ self w ~name ~ls (fun () -> k r)
+    schedule_task_ self w ~ls (fun () -> k r)
   in
 
   (* run the task now, catching errors *)
@@ -152,13 +143,12 @@ let run_task_now_ (self : state) ~runner (w : worker_state) ~name ~ls task :
      let bt = Printexc.get_raw_backtrace () in
      self.on_exn e bt);
 
-  exit_span_ ();
   after_task runner _ctx;
   w.cur_ls := Task_local_storage.Private_.Storage.dummy
 
-let[@inline] run_async_ (self : state) ~name ~ls (f : task) : unit =
+let[@inline] run_async_ (self : state) ~ls (f : task) : unit =
   let w = find_current_worker_ () in
-  schedule_task_ self w ~name ~ls f
+  schedule_task_ self w ~ls f
 
 (* TODO: function to schedule many tasks from the outside.
     - build a queue
@@ -204,7 +194,7 @@ let worker_run_self_tasks_ (self : state) ~runner w : unit =
     match WSQ.pop w.q with
     | Some task ->
       try_wake_someone_ self;
-      run_task_now_ self ~runner w ~name:task.name ~ls:task.ls task.f
+      run_task_now_ self ~runner w ~ls:task.ls task.f
     | None -> continue := false
   done
 
@@ -217,7 +207,7 @@ let worker_thread_ (self : state) ~(runner : t) (w : worker_state) : unit =
     worker_run_self_tasks_ self ~runner w;
     try_steal ()
   and run_task task : unit =
-    run_task_now_ self ~runner w ~name:task.name ~ls:task.ls task.f;
+    run_task_now_ self ~runner w ~ls:task.ls task.f;
     main ()
   and try_steal () =
     match try_to_steal_work_once_ self w with
@@ -276,7 +266,7 @@ type ('a, 'b) create_args =
   'a
 (** Arguments used in {!create}. See {!create} for explanations. *)
 
-let dummy_task_ = { f = ignore; ls = Task_local_storage.Private_.Storage.dummy ; name = "DUMMY_TASK" }
+let dummy_task_ = { f = ignore; ls = Task_local_storage.Private_.Storage.dummy ; }
 
 let create ?(on_init_thread = default_thread_init_exit_)
     ?(on_exit_thread = default_thread_init_exit_) ?(on_exn = fun _ _ -> ())
@@ -301,7 +291,6 @@ let create ?(on_init_thread = default_thread_init_exit_)
         {
           pool_id_;
           thread = dummy;
-          cur_span = Tracing_.dummy_span;
           q = WSQ.create ~dummy:dummy_task_ ();
           rng = Random.State.make [| i |];
           cur_ls = ref Task_local_storage.Private_.Storage.dummy;
@@ -326,7 +315,7 @@ let create ?(on_init_thread = default_thread_init_exit_)
   let runner =
     Runner.For_runner_implementors.create
       ~shutdown:(fun ~wait () -> shutdown_ pool ~wait)
-      ~run_async:(fun ~name ~ls f -> run_async_ pool ~name ~ls f)
+      ~run_async:(fun ~ls f -> run_async_ pool ~ls f)
       ~size:(fun () -> size_ pool)
       ~num_tasks:(fun () -> num_tasks_ pool)
       ()
diff --git a/src/fib/fiber.ml b/src/fib/fiber.ml
index 25a4485e..ebfd3319 100644
--- a/src/fib/fiber.ml
+++ b/src/fib/fiber.ml
@@ -148,9 +148,9 @@ let add_child_ ~protect (self : _ t) (child : _ t) =
 let k_current_fiber : any option Task_local_storage.key =
   Task_local_storage.new_key ~init:(fun () -> None) ()
 
-let spawn_ ?name ~on (f : _ -> 'a) : 'a t =
+let spawn_ ~on (f : _ -> 'a) : 'a t =
   let id = Handle.generate_fresh () in
-  let res, _promise = Fut.make ?name () in
+  let res, _promise = Fut.make () in
   let fib =
     {
       state = A.make @@ Alive { children = FM.empty; on_cancel = [] };
@@ -172,17 +172,17 @@ let spawn_ ?name ~on (f : _ -> 'a) : 'a t =
       resolve_as_failed_ fib ebt
   in
 
-  Runner.run_async on ?name run;
+  Runner.run_async on run;
 
   fib
 
-let[@inline] spawn_top ?name ~on f : _ t = spawn_ ?name ~on f
+let[@inline] spawn_top ~on f : _ t = spawn_ ~on f
 
-let spawn_link ?name ~protect f : _ t =
+let spawn_link ~protect f : _ t =
   match Task_local_storage.get k_current_fiber with
   | None -> failwith "Fiber.spawn_link: must be run from inside a fiber."
   | Some (Any parent) ->
-    let child = spawn_ ?name ~on:parent.runner f in
+    let child = spawn_ ~on:parent.runner f in
     add_child_ ~protect parent child;
     child
 
diff --git a/src/fib/fiber.mli b/src/fib/fiber.mli
index dc60b001..5b01948a 100644
--- a/src/fib/fiber.mli
+++ b/src/fib/fiber.mli
@@ -55,12 +55,12 @@ val on_result : 'a t -> 'a callback -> unit
     with the result. If the fiber is done already then the
     callback is invoked immediately with its result. *)
 
-val spawn_top : ?name:string -> on:Runner.t -> (unit -> 'a) -> 'a t
+val spawn_top : on:Runner.t -> (unit -> 'a) -> 'a t
 (** [spawn_top ~on f] spawns a new (toplevel) fiber onto the given runner.
     This fiber is not the child of any other fiber: its lifetime
     is only determined by the lifetime of [f()]. *)
 
-val spawn_link : ?name:string -> protect:bool -> (unit -> 'a) -> 'a t
+val spawn_link : protect:bool -> (unit -> 'a) -> 'a t
 (** [spawn_link ~protect f] spawns a sub-fiber [f_child]
     from a running fiber [parent].
     The sub-fiber [f_child] is attached to the current fiber and fails
diff --git a/src/forkjoin/moonpool_forkjoin.ml b/src/forkjoin/moonpool_forkjoin.ml
index 27aa1984..052ca7f2 100644
--- a/src/forkjoin/moonpool_forkjoin.ml
+++ b/src/forkjoin/moonpool_forkjoin.ml
@@ -135,7 +135,7 @@ let for_ ?chunk_size n (f : int -> int -> unit) : unit =
         let len_range = min chunk_size (n - offset) in
         assert (offset + len_range <= n);
 
-        run ~name:"" (fun () -> task_for ~offset ~len_range);
+        run (fun () -> task_for ~offset ~len_range);
         i := !i + len_range
       done
     in
diff --git a/test/effect-based/t_fib1.ml b/test/effect-based/t_fib1.ml
index 5a9d66e6..a2f62e82 100644
--- a/test/effect-based/t_fib1.ml
+++ b/test/effect-based/t_fib1.ml
@@ -20,7 +20,7 @@ let fib ~on x : int Fut.t =
       Fut.await t1 + Fut.await t2
     )
   in
-  Fut.spawn ~name:"fib" ~on (fun () -> fib_rec x)
+  Fut.spawn ~on (fun () -> fib_rec x)
 
 (* NOTE: for tracy support
    let () = Tracy_client_trace.setup ()