Revert "Merge pull request #38405 from JuliaLang/vc/distributed_ts"

Revert "fixup to pull request #38405 (#41641)"

Seems to be causing hanging in CI testing?

This reverts commit 5af1cf0.
This reverts commit 5a16805, reversing
changes made to 02807b2.

stdlib/Distributed/src/cluster.jl

@@ -95,14 +95,13 @@ end
 @enum WorkerState W_CREATED W_CONNECTED W_TERMINATING W_TERMINATED
 mutable struct Worker
  id::Int
- msg_lock::Threads.ReentrantLock # Lock for del_msgs, add_msgs, and gcflag
  del_msgs::Array{Any,1}
  add_msgs::Array{Any,1}
  gcflag::Bool
  state::WorkerState
- c_state::Threads.Condition # wait for state changes, lock for state
- ct_time::Float64  # creation time
- conn_func::Any  # used to setup connections lazily
+ c_state::Condition  # wait for state changes
+ ct_time::Float64 # creation time
+ conn_func::Any # used to setup connections lazily
 
  r_stream::IO
  w_stream::IO
@@ -134,7 +133,7 @@ mutable struct Worker
  if haskey(map_pid_wrkr, id)
  return map_pid_wrkr[id]
  end
- w=new(id, Threads.ReentrantLock(), [], [], false, W_CREATED, Threads.Condition(), time(), conn_func)
+ w=new(id, [], [], false, W_CREATED, Condition(), time(), conn_func)
  w.initialized = Event()
  register_worker(w)
  w
@@ -144,16 +143,12 @@ mutable struct Worker
 end
 
 function set_worker_state(w, state)
- lock(w.c_state) do
- w.state = state
- notify(w.c_state; all=true)
- end
+ w.state = state
+ notify(w.c_state; all=true)
 end
 
 function check_worker_state(w::Worker)
- lock(w.c_state)
  if w.state === W_CREATED
- unlock(w.c_state)
  if !isclusterlazy()
  if PGRP.topology === :all_to_all
  # Since higher pids connect with lower pids, the remote worker
@@ -173,8 +168,6 @@ function check_worker_state(w::Worker)
  errormonitor(t)
  wait_for_conn(w)
  end
- else
- unlock(w.c_state)
  end
 end
 
@@ -193,25 +186,13 @@ function exec_conn_func(w::Worker)
 end
 
 function wait_for_conn(w)
- lock(w.c_state)
  if w.state === W_CREATED
- unlock(w.c_state)
  timeout = worker_timeout() - (time() - w.ct_time)
  timeout <= 0 && error("peer $(w.id) has not connected to $(myid())")
 
- T = Threads.@spawn begin
- sleep($timeout)
- lock(w.c_state) do
- notify(w.c_state; all=true)
- end
- end
- errormonitor(T)
- lock(w.c_state) do
- wait(w.c_state)
- w.state === W_CREATED && error("peer $(w.id) didn't connect to $(myid()) within $timeout seconds")
- end
- else
- unlock(w.c_state)
+ @async (sleep(timeout); notify(w.c_state; all=true))
+ wait(w.c_state)
+ w.state === W_CREATED && error("peer $(w.id) didn't connect to $(myid()) within $timeout seconds")
  end
  nothing
 end
@@ -490,10 +471,6 @@ function addprocs_locked(manager::ClusterManager; kwargs...)
  # The `launch` method should add an object of type WorkerConfig for every
  # worker launched. It provides information required on how to connect
  # to it.
-
- # FIXME: launched should be a Channel, launch_ntfy should be a Threads.Condition
- # but both are part of the public interface. This means we currently can't use
- # `Threads.@spawn` in the code below.
  launched = WorkerConfig[]
  launch_ntfy = Condition()
 
@@ -506,10 +483,7 @@ function addprocs_locked(manager::ClusterManager; kwargs...)
  while true
  if isempty(launched)
  istaskdone(t_launch) && break
- @async begin
- sleep(1)
- notify(launch_ntfy)
- end
+ @async (sleep(1); notify(launch_ntfy))
  wait(launch_ntfy)
  end
 
@@ -662,12 +636,7 @@ function create_worker(manager, wconfig)
  # require the value of config.connect_at which is set only upon connection completion
  for jw in PGRP.workers
  if (jw.id != 1) && (jw.id < w.id)
- # wait for wl to join
- lock(jw.c_state) do
- if jw.state === W_CREATED
- wait(jw.c_state)
- end
- end
+ (jw.state === W_CREATED) && wait(jw.c_state)
  push!(join_list, jw)
  end
  end
@@ -690,12 +659,7 @@ function create_worker(manager, wconfig)
  end
 
  for wl in wlist
- lock(wl.c_state) do
- if wl.state === W_CREATED
- # wait for wl to join
- wait(wl.c_state)
- end
- end
+ (wl.state === W_CREATED) && wait(wl.c_state)
  push!(join_list, wl)
  end
  end
@@ -712,11 +676,7 @@ function create_worker(manager, wconfig)
  @async manage(w.manager, w.id, w.config, :register)
  # wait for rr_ntfy_join with timeout
  timedout = false
- @async begin
- sleep($timeout)
- timedout = true
- put!(rr_ntfy_join, 1)
- end
+ @async (sleep($timeout); timedout = true; put!(rr_ntfy_join, 1))
  wait(rr_ntfy_join)
  if timedout
  error("worker did not connect within $timeout seconds")

stdlib/Distributed/src/macros.jl

@@ -1,10 +1,14 @@
 # This file is a part of Julia. License is MIT: https://julialang.org/license
 
-let nextidx = Threads.Atomic{Int}(0)
+let nextidx = 0
  global nextproc
  function nextproc()
- idx = Threads.atomic_add!(nextidx, 1)
- return workers()[(idx % nworkers()) + 1]
+ p = -1
+ if p == -1
+ p = workers()[(nextidx % nworkers()) + 1]
+ nextidx += 1
+ end
+ p
  end
 end
 

stdlib/Distributed/src/managers.jl

@@ -163,7 +163,7 @@ function launch(manager::SSHManager, params::Dict, launched::Array, launch_ntfy:
  # Wait for all launches to complete.
  @sync for (i, (machine, cnt)) in enumerate(manager.machines)
  let machine=machine, cnt=cnt
- @async try
+  @async try
  launch_on_machine(manager, $machine, $cnt, params, launched, launch_ntfy)
  catch e
  print(stderr, "exception launching on machine $(machine) : $(e)\n")

stdlib/Distributed/src/messages.jl

@@ -126,20 +126,22 @@ function flush_gc_msgs(w::Worker)
  if !isdefined(w, :w_stream)
  return
  end
- lock(w.msg_lock) do
- w.gcflag || return # early exit if someone else got to this
- w.gcflag = false
- msgs = w.add_msgs
- w.add_msgs = Any[]
- if !isempty(msgs)
- remote_do(add_clients, w, msgs)
- end
+ w.gcflag = false
+ new_array = Any[]
+ msgs = w.add_msgs
+ w.add_msgs = new_array
+ if !isempty(msgs)
+ remote_do(add_clients, w, msgs)
+ end
 
- msgs = w.del_msgs
- w.del_msgs = Any[]
- if !isempty(msgs)
- remote_do(del_clients, w, msgs)
- end
+ # del_msgs gets populated by finalizers, so be very careful here about ordering of allocations
+ # XXX: threading requires this to be atomic
+ new_array = Any[]
+ msgs = w.del_msgs
+ w.del_msgs = new_array
+ if !isempty(msgs)
+ #print("sending delete of $msgs\n")
+ remote_do(del_clients, w, msgs)
  end
 end
 

stdlib/Distributed/src/remotecall.jl

@@ -247,42 +247,22 @@ function del_clients(pairs::Vector)
  end
 end
 
-# The task below is coalescing the `flush_gc_msgs` call
-# across multiple producers, see `send_del_client`,
-# and `send_add_client`.
-# XXX: Is this worth the additional complexity?
-# `flush_gc_msgs` has to iterate over all connected workers.
-const any_gc_flag = Threads.Condition()
+const any_gc_flag = Condition()
 function start_gc_msgs_task()
- errormonitor(
- Threads.@spawn begin
- while true
- lock(any_gc_flag) do
- wait(any_gc_flag)
- flush_gc_msgs() # handles throws internally
- end
- end
- end
- )
+ errormonitor(@async while true
+ wait(any_gc_flag)
+ flush_gc_msgs()
+ end)
 end
 
-# Function can be called within a finalizer
 function send_del_client(rr)
  if rr.where == myid()
  del_client(rr)
  elseif id_in_procs(rr.where) # process only if a valid worker
  w = worker_from_id(rr.where)::Worker
- msg = (remoteref_id(rr), myid())
- # We cannot acquire locks from finalizers
- Threads.@spawn begin
- lock(w.msg_lock) do
- push!(w.del_msgs, msg)
- w.gcflag = true
- end
- lock(any_gc_flag) do
- notify(any_gc_flag)
- end
- end
+ push!(w.del_msgs, (remoteref_id(rr), myid()))
+ w.gcflag = true
+ notify(any_gc_flag)
  end
 end
 
@@ -308,13 +288,9 @@ function send_add_client(rr::AbstractRemoteRef, i)
  # to the processor that owns the remote ref. it will add_client
  # itself inside deserialize().
  w = worker_from_id(rr.where)
- lock(w.msg_lock) do
- push!(w.add_msgs, (remoteref_id(rr), i))
- w.gcflag = true
- end
- lock(any_gc_flag) do
- notify(any_gc_flag)
- end
+ push!(w.add_msgs, (remoteref_id(rr), i))
+ w.gcflag = true
+ notify(any_gc_flag)
  end
 end
 

stdlib/Distributed/test/distributed_exec.jl

@@ -1696,5 +1696,4 @@ include("splitrange.jl")
 # Run topology tests last after removing all workers, since a given
 # cluster at any time only supports a single topology.
 rmprocs(workers())
-include("threads.jl")
 include("topology.jl")