From ba10819800aa70d702633d18ecc58ebfc74be8d0 Mon Sep 17 00:00:00 2001
From: Eric Holk <eric.holk@gmail.com>
Date: Thu, 12 Jul 2012 15:57:12 -0700
Subject: [PATCH] Added a message send that uses shared chans. They are slower
 than port selectors, but scale better.

---
 src/test/bench/msgsend-pipes-shared.rs | 208 +++++++++++++++++++++++++
 1 file changed, 208 insertions(+)
 create mode 100644 src/test/bench/msgsend-pipes-shared.rs

diff --git a/src/test/bench/msgsend-pipes-shared.rs b/src/test/bench/msgsend-pipes-shared.rs
new file mode 100644
index 000000000000..ea4834609537
--- /dev/null
+++ b/src/test/bench/msgsend-pipes-shared.rs
@@ -0,0 +1,208 @@
+// A port of the simplistic benchmark from
+//
+//    http://github.com/PaulKeeble/ScalaVErlangAgents
+//
+// I *think* it's the same, more or less.
+
+// This version uses pipes with a shared send endpoint. It should have
+// different scalability characteristics compared to the select
+// version.
+
+use std;
+import io::writer;
+import io::writer_util;
+
+import arc::methods;
+import pipes::{port, chan};
+
+macro_rules! move {
+    { $x:expr } => { unsafe { let y <- *ptr::addr_of($x); y } }
+}
+
+enum request {
+    get_count,
+    bytes(uint),
+    stop
+}
+
+fn server(requests: port<request>, responses: pipes::chan<uint>) {
+    let mut count = 0u;
+    let mut done = false;
+    while !done {
+        alt requests.try_recv() {
+          some(get_count) { responses.send(copy count); }
+          some(bytes(b)) {
+            //#error("server: received %? bytes", b);
+            count += b;
+          }
+          none { done = true; }
+          _ { }
+        }
+    }
+    responses.send(count);
+    //#error("server exiting");
+}
+
+fn run(args: &[str]) {
+    let (to_parent, from_child) = pipes::stream();
+    let (to_child, from_parent) = pipes::stream();
+
+    let to_child = shared_chan(to_child);
+
+    let size = option::get(uint::from_str(args[1]));
+    let workers = option::get(uint::from_str(args[2]));
+    let num_bytes = 100;
+    let start = std::time::precise_time_s();
+    let mut worker_results = ~[];
+    for uint::range(0u, workers) |i| {
+        let builder = task::builder();
+        vec::push(worker_results, task::future_result(builder));
+        let to_child = to_child.clone();
+        do task::run(builder) {
+            for uint::range(0u, size / workers) |_i| {
+                //#error("worker %?: sending %? bytes", i, num_bytes);
+                to_child.send(bytes(num_bytes));
+            }
+            //#error("worker %? exiting", i);
+        };
+    }
+    do task::spawn {
+        server(from_parent, to_parent);
+    }
+
+    vec::iter(worker_results, |r| { future::get(r); } );
+    //#error("sending stop message");
+    to_child.send(stop);
+    move!{to_child};
+    let result = from_child.recv();
+    let end = std::time::precise_time_s();
+    let elapsed = end - start;
+    io::stdout().write_str(#fmt("Count is %?\n", result));
+    io::stdout().write_str(#fmt("Test took %? seconds\n", elapsed));
+    let thruput = ((size / workers * workers) as float) / (elapsed as float);
+    io::stdout().write_str(#fmt("Throughput=%f per sec\n", thruput));
+    assert result == num_bytes * size;
+}
+
+fn main(args: ~[str]) {
+    let args = if os::getenv("RUST_BENCH").is_some() {
+        ~["", "1000000", "10000"]
+    } else if args.len() <= 1u {
+        ~["", "10000", "4"]
+    } else {
+        copy args
+    };        
+
+    #debug("%?", args);
+    run(args);
+}
+
+// Treat a whole bunch of ports as one.
+class box<T> {
+    let mut contents: option<T>;
+    new(+x: T) { self.contents = some(x); }
+
+    fn swap(f: fn(+T) -> T) {
+        let mut tmp = none;
+        self.contents <-> tmp;
+        self.contents = some(f(option::unwrap(tmp)));
+    }
+
+    fn unwrap() -> T {
+        let mut tmp = none;
+        self.contents <-> tmp;
+        option::unwrap(tmp)
+    }
+}
+
+class port_set<T: send> {
+    let mut ports: ~[pipes::port<T>];
+
+    new() { self.ports = ~[]; }
+
+    fn add(+port: pipes::port<T>) {
+        vec::push(self.ports, port)
+    }
+
+    fn try_recv() -> option<T> {
+        let mut result = none;
+        while result == none && self.ports.len() > 0 {
+            let i = pipes::wait_many(self.ports.map(|p| p.header()));
+            // dereferencing an unsafe pointer nonsense to appease the
+            // borrowchecker.
+            alt unsafe {(*ptr::addr_of(self.ports[i])).try_recv()} {
+              some(m) {
+                result = some(move!{m});
+              }
+              none {
+                // Remove this port.
+                let mut ports = ~[];
+                self.ports <-> ports;
+                vec::consume(ports,
+                             |j, x| if i != j { vec::push(self.ports, x) });
+              }
+            }
+        }
+/*        
+        while !done {
+            do self.ports.swap |ports| {
+                if ports.len() > 0 {
+                    let old_len = ports.len();
+                    let (_, m, ports) = pipes::select(ports);
+                    alt m {
+                      some(pipes::streamp::data(x, next)) {
+                        result = some(move!{x});
+                        done = true;
+                        assert ports.len() == old_len - 1;
+                        vec::append_one(ports, move!{next})
+                      }
+                      none {
+                        //#error("pipe closed");
+                        assert ports.len() == old_len - 1;
+                        ports
+                      }
+                    }
+                }
+                else {
+                    //#error("no more pipes");
+                    done = true;
+                    ~[]
+                }
+            }
+        }
+*/
+        result
+    }
+
+    fn recv() -> T {
+        option::unwrap(self.try_recv())
+    }
+}
+
+impl private_methods/&<T: send> for pipes::port<T> {
+    pure fn header() -> *pipes::packet_header unchecked {
+        alt self.endp {
+          some(endp) {
+            endp.header()
+          }
+          none { fail "peeking empty stream" }
+        }
+    }
+}
+
+type shared_chan<T: send> = arc::exclusive<pipes::chan<T>>;
+
+impl chan<T: send> for shared_chan<T> {
+    fn send(+x: T) {
+        let mut xx = some(x);
+        do self.with |_c, chan| {
+            let mut x = none;
+            x <-> xx;
+            chan.send(option::unwrap(x))
+        }
+    }
+}
+
+fn shared_chan<T:send>(+c: pipes::chan<T>) -> shared_chan<T> {
+    arc::exclusive(c)
+}
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