--- a/README.md	Sun Feb 14 15:23:51 2016 +0100
+++ b/README.md	Sun Feb 14 16:22:50 2016 +0100
@@ -35,7 +35,7 @@
         pub fn set(&mut self, k: String, v: State);
         // Obtain current timestamp.
         pub fn now() -> i64;
-        // Time (Unix epoch) of last call.
+        // Time (in milliseconds since Unix epoch) of last call.
         pub last_called: i64;
     }
     pub enum State {
@@ -48,8 +48,9 @@
 
 Every time your metric is asked to `render()`, it is given the same
 `MetricState` object; `last_called` is set to the timestamp of the previous
-invocation (so you can compute a rate, for example); it has second-resolution.
-You can arbitrarily get and set values on the `MetricState`.
+invocation (so you can compute a rate, for example); it has millisecond
+resolution and is 0 on first invocation. You can arbitrarily get and set values
+on the `MetricState`.
 
 Typically you will set some constant configuration parameters at the invocation
 of your `init()` method, and use them later to determine how exactly you'll

--- a/src/framework.rs	Sun Feb 14 15:23:51 2016 +0100
+++ b/src/framework.rs	Sun Feb 14 16:22:50 2016 +0100
@@ -5,7 +5,7 @@
 use std::time::Duration;
 
 extern crate chrono;
-use self::chrono::Local;
+use self::chrono as chron;
 
 #[derive(Clone)]
 pub enum Color {
@@ -96,8 +96,11 @@
     pub fn set(&mut self, k: String, v: State) {
         self.state.insert(k, v);
     }
+    /// Returns timestamp in epoch milliseconds.
     pub fn now() -> i64 {
-        Local::now().timestamp()
+        use self::chrono::Timelike;
+        let t = chron::Local::now();
+        t.timestamp() + t.nanosecond() as i64 / 1000000
     }
 }
 
@@ -135,7 +138,7 @@
 }
 
 pub fn render_loop(mut metrics: Vec<ActiveMetric>, interval: i32) {
-    let ival_duration = Duration::new(interval as u64, 0);
+    let ival_duration = Duration::new((interval / 1000) as u64, 1000000 * (interval as u32 % 1000));
     let intro = "{\"version\":1}\n[[]\n";
     print!("{}", intro);
 

--- a/src/main.rs	Sun Feb 14 15:23:51 2016 +0100
+++ b/src/main.rs	Sun Feb 14 16:22:50 2016 +0100
@@ -30,7 +30,7 @@
                        "METRIC1,METRIC2,METRIC3");
         options.optopt("",
                        "interval",
-                       "Interval in seconds between individual render cycles. Default: 1",
+                       "Interval in milliseconds between individual render cycles. Default: 1000",
                        "SECONDS");
         options.optflag("h", "help", "Print a help text");
 
@@ -111,9 +111,9 @@
         });
 
         let interval = i32::from_str_radix(&matches.opt_str("interval")
-                                                   .unwrap_or(String::from("1")),
+                                                   .unwrap_or(String::from("1000")),
                                            10)
-                           .unwrap_or(1);
+                           .unwrap_or(1000);
 
         (metrics, interval)
     }