From 4dfe0db0f4e54337cd6727cd29e1ad44aca50178 Mon Sep 17 00:00:00 2001
From: Sean McArthur <sean.monstar@gmail.com>
Date: Fri, 23 Jun 2017 18:52:32 -0700
Subject: [PATCH] perf(server): dont record Idle time when not needed

---
 src/client/pool.rs | 29 ++++++++++++++++++++---------
 src/http/conn.rs   | 12 ++++--------
 src/http/io.rs     |  8 +++++++-
 3 files changed, 31 insertions(+), 18 deletions(-)

diff --git a/src/client/pool.rs b/src/client/pool.rs
index 042ac03e..c8665792 100644
--- a/src/client/pool.rs
+++ b/src/client/pool.rs
@@ -80,7 +80,7 @@ impl<T: Clone> Pool<T> {
             entry: Entry {
                 value: value,
                 is_reused: false,
-                status: Rc::new(Cell::new(KA::Busy)),
+                status: Rc::new(Cell::new(TimedKA::Busy)),
             },
             key: key,
             pool: self.clone(),
@@ -94,7 +94,7 @@ impl<T: Clone> Pool<T> {
     fn reuse(&self, key: Rc<String>, mut entry: Entry<T>) -> Pooled<T> {
         trace!("Pool::reuse {:?}", key);
         entry.is_reused = true;
-        entry.status.set(KA::Busy);
+        entry.status.set(TimedKA::Busy);
         Pooled {
             entry: entry,
             key: key,
@@ -141,17 +141,17 @@ impl<T> DerefMut for Pooled<T> {
 
 impl<T: Clone> KeepAlive for Pooled<T> {
     fn busy(&mut self) {
-        self.entry.status.set(KA::Busy);
+        self.entry.status.set(TimedKA::Busy);
     }
 
     fn disable(&mut self) {
-        self.entry.status.set(KA::Disabled);
+        self.entry.status.set(TimedKA::Disabled);
     }
 
     fn idle(&mut self) {
         let previous = self.status();
-        self.entry.status.set(KA::Idle(Instant::now()));
-        if let KA::Idle(..) = previous {
+        self.entry.status.set(TimedKA::Idle(Instant::now()));
+        if let KA::Idle = previous {
             trace!("Pooled::idle already idle");
             return;
         }
@@ -162,7 +162,11 @@ impl<T: Clone> KeepAlive for Pooled<T> {
     }
 
     fn status(&self) -> KA {
-        self.entry.status.get()
+        match self.entry.status.get() {
+            TimedKA::Idle(_) => KA::Idle,
+            TimedKA::Busy => KA::Busy,
+            TimedKA::Disabled => KA::Disabled,
+        }
     }
 }
 
@@ -187,7 +191,14 @@ impl<T: Clone> BitAndAssign<bool> for Pooled<T> {
 struct Entry<T> {
     value: T,
     is_reused: bool,
-    status: Rc<Cell<KA>>,
+    status: Rc<Cell<TimedKA>>,
+}
+
+#[derive(Clone, Copy, Debug)]
+enum TimedKA {
+    Idle(Instant),
+    Busy,
+    Disabled,
 }
 
 pub struct Checkout<T> {
@@ -224,7 +235,7 @@ impl<T: Clone> Future for Checkout<T> {
             trace!("Checkout::poll key found {:?}", key);
             while let Some(entry) = list.pop() {
                 match entry.status.get() {
-                    KA::Idle(idle_at) if !expiration.expires(idle_at) => {
+                    TimedKA::Idle(idle_at) if !expiration.expires(idle_at) => {
                         trace!("Checkout::poll found idle client for {:?}", key);
                         should_remove = list.is_empty();
                         return Some(entry);
diff --git a/src/http/conn.rs b/src/http/conn.rs
index bb2cee0b..890740db 100644
--- a/src/http/conn.rs
+++ b/src/http/conn.rs
@@ -1,7 +1,6 @@
 use std::fmt;
 use std::io::{self, Write};
 use std::marker::PhantomData;
-use std::time::Instant;
 
 use futures::{Poll, Async, AsyncSink, Stream, Sink, StartSend};
 use futures::task::Task;
@@ -228,10 +227,7 @@ where I: AsyncRead + AsyncWrite,
 
         let wants_keep_alive = head.should_keep_alive();
         self.state.keep_alive &= wants_keep_alive;
-        let mut buf = Vec::new();
-        let encoder = T::encode(head, &mut buf);
-        //TODO: handle when there isn't enough room to buffer the head
-        assert!(self.io.buffer(buf) > 0);
+        let encoder = T::encode(head, self.io.write_buf_mut());
         self.state.writing = if body {
             Writing::Body(encoder, None)
         } else {
@@ -534,7 +530,7 @@ pub trait KeepAlive: fmt::Debug + ::std::ops::BitAndAssign<bool> {
 
 #[derive(Clone, Copy, Debug)]
 pub enum KA {
-    Idle(Instant),
+    Idle,
     Busy,
     Disabled,
 }
@@ -547,7 +543,7 @@ impl Default for KA {
 
 impl KeepAlive for KA {
     fn idle(&mut self) {
-        *self = KA::Idle(Instant::now());
+        *self = KA::Idle;
     }
 
     fn busy(&mut self) {
@@ -595,7 +591,7 @@ impl<B, K: KeepAlive> State<B, K> {
     }
 
     fn is_idle(&self) -> bool {
-        if let KA::Idle(..) = self.keep_alive.status() {
+        if let KA::Idle = self.keep_alive.status() {
             true
         } else {
             false
diff --git a/src/http/io.rs b/src/http/io.rs
index 1d942868..ab26a013 100644
--- a/src/http/io.rs
+++ b/src/http/io.rs
@@ -42,6 +42,12 @@ impl<T: AsyncRead + AsyncWrite> Buffered<T> {
         self.read_buf.as_ref()
     }
 
+    pub fn write_buf_mut(&mut self) -> &mut Vec<u8> {
+        self.write_buf.maybe_reset();
+        self.write_buf.maybe_reserve(0);
+        &mut self.write_buf.0.bytes
+    }
+
     pub fn consume_leading_lines(&mut self) {
         if !self.read_buf.is_empty() {
             let mut i = 0;
@@ -133,7 +139,7 @@ impl<T: Write> Write for Buffered<T> {
         } else {
             loop {
                 let n = try!(self.write_buf.write_into(&mut self.io));
-                debug!("flushed {} bytes", n);
+                trace!("flushed {} bytes", n);
                 if self.write_buf.remaining() == 0 {
                     break;
                 }