Added a new version of pfib that's better suited for benchmarking the task system. It generates gnuplot output.

Author: Eric Holk

src/test/bench/task-perf/pfib.rs

@@ -0,0 +1,79 @@
+// -*- rust -*-
+
+/*
+  A parallel version of fibonacci numbers.
+
+  This version is meant mostly as a way of stressing and benchmarking
+  the task system. It supports a lot of command-line arguments to
+  control how it runs.
+
+*/
+
+use std;
+
+import std::vec;
+import std::uint;
+import std::time;
+import std::str;
+import std::int::range;
+import std::io;
+
+fn recv[T](&port[T] p) -> T {
+    let T x;
+    p |> x;
+    ret x;
+}
+
+fn fib(int n) -> int {
+    fn pfib(chan[int] c, int n) {
+        if (n == 0) {
+            c <| 0;
+        }
+        else if (n <= 2) {
+            c <| 1;
+        }
+        else {
+            let port[int] p = port();
+      
+            auto t1 = spawn pfib(chan(p), n - 1);
+            auto t2 = spawn pfib(chan(p), n - 2);
+
+            c <| recv(p) + recv(p);
+        }
+    }
+
+    let port[int] p = port();
+    auto t = spawn pfib(chan(p), n);
+    ret recv(p);
+}
+
+fn main(vec[str] argv) {
+    if(vec::len(argv) == 1u) {
+        assert (fib(8) == 21);
+        assert (fib(15) == 610);
+        log fib(8);
+        log fib(15);
+    }
+    else {
+        // Interactive mode! Wooo!!!!
+
+        auto max = uint::parse_buf(str::bytes(argv.(1)), 10u) as int;
+
+        auto num_trials = 10;
+
+        auto out = io::stdout();
+
+        for each(int n in range(1, max + 1)) {
+            for each(int i in range(0, num_trials)) {
+                auto start = time::precise_time_ns();
+                auto fibn = fib(n);
+                auto stop = time::precise_time_ns();
+
+                auto elapsed = (stop - start) as int;
+            
+                out.write_line(#fmt("%d\t%d\t%d", n, fibn, elapsed));
+            }
+        }
+
+    }
+}