tiny_httpd: use picos semaphore; tweak pool size, buf size

dune-project

@@ -40,7 +40,8 @@
   ocaml
   dune
   nanoev
-  picos
+  (picos (>= 0.6))
+  picos_std
   (tiny_httpd (>= 0.17)))
  (tags (nanoev http)))
 

nanoev_tiny_httpd.opam

@@ -11,7 +11,8 @@ depends: [
   "ocaml"
   "dune" {>= "2.7"}
   "nanoev"
-  "picos"
+  "picos" {>= "0.6"}
+  "picos_std"
   "tiny_httpd" {>= "0.17"}
   "odoc" {with-doc}
 ]

src/tiny_httpd/dune

@@ -6,5 +6,6 @@
   picos
   (re_export nanoev)
   nanoev.picos
+  picos_std.sync
   (re_export iostream)
   (re_export tiny_httpd)))

src/tiny_httpd/nanoev_tiny_httpd.ml

@@ -5,45 +5,8 @@ module Slice = Iostream.Slice
 module Pool = TH.Pool
 module Buf = TH.Buf
 
-let unwrap_ = function
-  | None -> ()
-  | Some (exn, bt) -> Printexc.raise_with_backtrace exn bt
-
+module Sem_ = Picos_std_sync.Semaphore.Counting
 (** Non blocking semaphore *)
-module Sem_ = struct
-  type t = {
-    mutable n: int;
-    max: int;
-    waiting: Picos.Trigger.t Queue.t;
-    mutex: Mutex.t;
-  }
-
-  let create n =
-    if n <= 0 then invalid_arg "Semaphore.create";
-    { n; max = n; mutex = Mutex.create (); waiting = Queue.create () }
-
-  let acquire self =
-    Mutex.lock self.mutex;
-    while self.n = 0 do
-      let tr = Picos.Trigger.create () in
-      Queue.push tr self.waiting;
-      Mutex.unlock self.mutex;
-      let res = Picos.Trigger.await tr in
-      unwrap_ res;
-      Mutex.lock self.mutex
-    done;
-    assert (self.n > 0);
-    self.n <- self.n - 1;
-    Mutex.unlock self.mutex
-
-  let release self =
-    Mutex.lock self.mutex;
-    self.n <- self.n + 1;
-    Option.iter Picos.Trigger.signal (Queue.take_opt self.waiting);
-    Mutex.unlock self.mutex
-
-  let num_acquired self = self.max - self.n
-end
 
 module Out = struct
   open Iostream
@@ -147,7 +110,7 @@ module Unix_tcp_server_ = struct
     new_thread: (unit -> unit) -> unit;
     timeout: float;
     masksigpipe: bool;
-    mutable running: bool; (* TODO: use an atomic? *)
+    running: bool Atomic.t;
   }
 
   let shutdown_silent_ fd =
@@ -183,7 +146,7 @@ module Unix_tcp_server_ = struct
             let inet_addr = Unix.inet_addr_of_string self.addr in
             Unix.setsockopt sock Unix.SO_REUSEADDR true;
             Unix.bind sock (Unix.ADDR_INET (inet_addr, self.port));
-            let n_listen = 2 * self.max_connections in
+            let n_listen = self.max_connections in
             Unix.listen sock n_listen
           );
 
@@ -191,10 +154,16 @@ module Unix_tcp_server_ = struct
 
           let tcp_server =
             {
-              TH.IO.TCP_server.stop = (fun () -> self.running <- false);
-              running = (fun () -> self.running);
+              TH.IO.TCP_server.stop =
+                (fun () ->
+                  Atomic.set self.running false;
+
+                  (* close accept socket so the main loop will return *)
+                  try Unix.close sock with _ -> ());
+              running = (fun () -> Atomic.get self.running);
               active_connections =
-                (fun () -> Sem_.num_acquired self.sem_max_connections);
+                (fun () ->
+                  self.max_connections - Sem_.get_value self.sem_max_connections);
               endpoint =
                 (fun () ->
                   let addr, port = get_addr_ sock in
@@ -233,7 +202,7 @@ module Unix_tcp_server_ = struct
           in
 
           Unix.set_nonblock sock;
-          while self.running do
+          while Atomic.get self.running do
             match EV.accept sock with
             | client_sock, client_addr ->
               (* limit concurrency *)
@@ -272,7 +241,7 @@ module Unix_tcp_server_ = struct
           done;
 
           (* Wait for all threads to be done: this only works if all threads are done. *)
-          Unix.close sock;
+          (try Unix.close sock with _ -> ());
           (* TODO? *)
           (* Sem_.acquire self.sem_max_connections.max self.sem_max_connections; *)
           ());
@@ -290,11 +259,16 @@ open struct
     slice.len <- 0
 end
 
-let create ?(masksigpipe = not Sys.win32) ?max_connections ?(timeout = 0.0)
-    ?buf_size ?(get_time_s = Unix.gettimeofday) ?(addr = "127.0.0.1")
-    ?(port = 8080) ?sock ?middlewares ~new_thread () : TH.Server.t =
+let create ?(masksigpipe = not Sys.win32) ?max_connections ?max_buf_pool_size
+    ?(timeout = 0.0) ?buf_size ?(get_time_s = Unix.gettimeofday)
+    ?(addr = "127.0.0.1") ?(port = 8080) ?sock ?middlewares ~new_thread () :
+    TH.Server.t =
   let max_connections = get_max_connection_ ?max_connections () in
-  let max_pool_size = min 4096 max_connections * 2 in
+  let max_pool_size =
+    match max_buf_pool_size with
+    | None -> min 4096 max_connections * 2
+    | Some m -> m
+  in
   let server =
     {
       Unix_tcp_server_.addr;
@@ -309,11 +283,11 @@ let create ?(masksigpipe = not Sys.win32) ?max_connections ?(timeout = 0.0)
             (let buf_size = Option.value buf_size ~default:4096 in
              fun () -> Slice.create buf_size)
           ();
-      running = true;
+      running = Atomic.make true;
       port;
       sock;
       max_connections;
-      sem_max_connections = Sem_.create max_connections;
+      sem_max_connections = Sem_.make max_connections;
       masksigpipe;
       timeout;
     }

src/tiny_httpd/nanoev_tiny_httpd.mli

@@ -3,6 +3,7 @@ module TH = Tiny_httpd_core
 val create :
   ?masksigpipe:bool ->
   ?max_connections:int ->
+  ?max_buf_pool_size:int ->
   ?timeout:float ->
   ?buf_size:int ->
   ?get_time_s:(unit -> float) ->