metrics: Add support for microsecond counters (#772)

Also fix broken summary support; and ensure that all features are
checked in CI.

Author: olix0r

Cargo.lock

@@ -1245,7 +1245,7 @@ dependencies = [
  "indexmap",
  "parking_lot",
  "quickcheck",
- "tokio 0.2.23",
+ "tokio 0.3.5",
  "tracing",
 ]
 
@@ -2581,7 +2581,6 @@ dependencies = [
  "memchr 2.3.3",
  "pin-project-lite 0.1.4",
  "slab",
- "tokio-macros 0.2.6",
  "tracing",
 ]
 
@@ -2603,7 +2602,7 @@ dependencies = [
  "pin-project-lite 0.2.0",
  "signal-hook-registry",
  "slab",
- "tokio-macros 0.3.1",
+ "tokio-macros",
  "winapi 0.3.8",
 ]
 
@@ -2637,17 +2636,6 @@ dependencies = [
  "log",
 ]
 
-[[package]]
-name = "tokio-macros"
-version = "0.2.6"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e44da00bfc73a25f814cd8d7e57a68a5c31b74b3152a0a1d1f590c97ed06265a"
-dependencies = [
- "proc-macro2",
- "quote",
- "syn",
-]
-
 [[package]]
 name = "tokio-macros"
 version = "0.3.1"

linkerd/metrics/Cargo.toml

@@ -18,9 +18,9 @@ http = "0.2"
 hyper = "0.14.0-dev"
 indexmap = "1.0"
 parking_lot = { version = "0.11", optional = true }
-tokio = { version = "0.2", features = ["time"], optional = true }
+tokio = { version = "0.3", features = ["time"], optional = true }
 tracing = "0.1.2"
 
 [dev-dependencies]
 quickcheck = { version = "0.9", default-features = false }
-tokio = { version = "0.2", features = ["macros", "test-util", "time"] }
+tokio = { version = "0.3", features = ["macros", "rt-multi-thread", "test-util", "time"] }

linkerd/metrics/src/counter.rs

@@ -94,7 +94,7 @@ impl<F: Factor> FmtMetric for Counter<F> {
 #[cfg(test)]
 mod tests {
     use super::*;
-    use crate::{MillisAsSeconds, MAX_PRECISE_UINT64};
+    use crate::{MicrosAsSeconds, MillisAsSeconds, MAX_PRECISE_UINT64};
 
     #[test]
     fn count_simple() {
@@ -140,4 +140,24 @@ mod tests {
         let max = Counter::<MillisAsSeconds>::from(MAX_PRECISE_UINT64 * 1000);
         assert_eq!(max.value(), MAX_PRECISE_UINT64 as f64);
     }
+
+    #[test]
+    fn micros_as_seconds() {
+        let c = Counter::<MicrosAsSeconds>::from(1);
+        assert_eq!(c.value(), 0.000_001);
+        c.add(110);
+        assert_eq!(c.value(), 0.000_111);
+
+        let c = Counter::<MicrosAsSeconds>::from((MAX_PRECISE_UINT64 - 1) * 1000);
+        assert_eq!(c.value(), (MAX_PRECISE_UINT64 - 1) as f64 * 0.001);
+        c.add(1_000);
+        assert_eq!(c.value(), MAX_PRECISE_UINT64 as f64 * 0.001);
+        c.add(1_000);
+        assert_eq!(c.value(), 0.0);
+        c.add(1);
+        assert_eq!(c.value(), 0.000_001);
+
+        let max = Counter::<MicrosAsSeconds>::from(MAX_PRECISE_UINT64 * 1000);
+        assert_eq!(max.value(), MAX_PRECISE_UINT64 as f64 * 0.001);
+    }
 }

linkerd/metrics/src/lib.rs

@@ -40,6 +40,8 @@ pub trait Factor {
     fn factor(n: u64) -> f64;
 }
 
+pub struct MicrosAsSeconds;
+
 pub struct MillisAsSeconds;
 
 /// Largest `u64` that can fit without loss of precision in `f64` (2^53).
@@ -60,3 +62,9 @@ impl Factor for MillisAsSeconds {
         n.wrapping_rem((MAX_PRECISE_UINT64 + 1) * 1000) as f64 * 0.001
     }
 }
+
+impl Factor for MicrosAsSeconds {
+    fn factor(n: u64) -> f64 {
+        n.wrapping_rem((MAX_PRECISE_UINT64 + 1) * 1_000) as f64 * 0.000_001
+    }
+}

linkerd/metrics/src/summary.rs

@@ -154,7 +154,7 @@ impl<F> Summary<F> {
     /// necessary.
     #[inline]
     fn rotated_window_mut(&self) -> MappedMutexGuard<'_, Histogram<u64>> {
-        let mut w = self.windows.write();
+        let mut w = self.windows.lock();
         let now = time::Instant::now();
         if now >= w.next_rotate {
             // Advance windows per elapsed time. If the more than one interval
@@ -178,7 +178,7 @@ impl<F> Summary<F> {
         let mut report = self.report.lock();
         // Remove all values from the merged
         report.reset();
-        let windows = self.windows.read();
+        let windows = self.windows.lock();
         for w in windows.active.iter() {
             // The report histogram must have been created with the same
             // configuration as the other histograms, so they all either share a