From d0a9a47ea35e5b37455b2a10eb075a78fbb04508 Mon Sep 17 00:00:00 2001
From: Derek Collison <derek.collison@gmail.com>
Date: Sun, 3 Apr 2016 05:41:45 -0700
Subject: [PATCH] L1 client cache for sublist and accounting optimizations

---
 server/client.go  | 70 +++++++++++++++++++++++++++++++++++++----------
 server/sublist.go |  4 ++-
 2 files changed, 58 insertions(+), 16 deletions(-)

diff --git a/server/client.go b/server/client.go
index 4f5a61e9..84528d23 100644
--- a/server/client.go
+++ b/server/client.go
@@ -46,6 +46,7 @@ type client struct {
 	bw    *bufio.Writer
 	srv   *Server
 	subs  map[string]*subscription
+	cache readCache
 	pcd   map[*client]struct{}
 	atmr  *time.Timer
 	ptmr  *time.Timer
@@ -59,6 +60,14 @@ type client struct {
 	trace bool
 }
 
+// Used in readloop to cache hot subject lookups and group statistics.
+type readCache struct {
+	genid   uint64
+	inMsgs  int64
+	inBytes int64
+	subs    map[string][]*subscription
+}
+
 func (c *client) String() (id string) {
 	return c.ncs
 }
@@ -154,6 +163,8 @@ func (c *client) readLoop() {
 		return
 	}
 
+	// read buffer
+	// FIXME(dlc) make dynamic
 	b := make([]byte, s.opts.BufSize)
 
 	for {
@@ -164,6 +175,11 @@ func (c *client) readLoop() {
 		}
 		// Grab for updates for last activity.
 		last := time.Now()
+
+		// Clear inbound stats cache
+		c.cache.inMsgs = 0
+		c.cache.inBytes = 0
+
 		if err := c.parse(b[:n]); err != nil {
 			// handled inline
 			if err != ErrMaxPayload && err != ErrAuthorization {
@@ -173,6 +189,13 @@ func (c *client) readLoop() {
 			}
 			return
 		}
+		// Updates stats for client and server that were collected
+		// from parsing through the buffer.
+		atomic.AddInt64(&c.inMsgs, c.cache.inMsgs)
+		atomic.AddInt64(&c.inBytes, c.cache.inBytes)
+		atomic.AddInt64(&s.inMsgs, c.cache.inMsgs)
+		atomic.AddInt64(&s.inBytes, c.cache.inBytes)
+
 		// Check pending clients for flush.
 		for cp := range c.pcd {
 			// Flush those in the set
@@ -717,20 +740,20 @@ writeErr:
 
 // processMsg is called to process an inbound msg from a client.
 func (c *client) processMsg(msg []byte) {
-
-	// Update statistics
-
-	// The msg includes the CR_LF, so pull back out for accounting.
-	msgSize := int64(len(msg) - LEN_CR_LF)
-
-	// Since we don't grab the client's lock, use atomic here.
-	// Monitor will also use atomic to read those.
-	atomic.AddInt64(&c.inMsgs, 1)
-	atomic.AddInt64(&c.inBytes, msgSize)
-
 	// Snapshot server.
 	srv := c.srv
 
+	// Create cache subs map if needed.
+	if c.cache.subs == nil && srv != nil {
+		c.cache.subs = make(map[string][]*subscription)
+		c.cache.genid = atomic.LoadUint64(&srv.sl.genid)
+	}
+
+	// Update statistics
+	// The msg includes the CR_LF, so pull back out for accounting.
+	c.cache.inMsgs += 1
+	c.cache.inBytes += int64(len(msg) - LEN_CR_LF)
+
 	if c.trace {
 		c.traceMsg(msg)
 	}
@@ -741,11 +764,28 @@ func (c *client) processMsg(msg []byte) {
 		return
 	}
 
-	// Accounting
-	atomic.AddInt64(&srv.inMsgs, 1)
-	atomic.AddInt64(&srv.inBytes, msgSize)
+	var genid uint64
+	var r []*subscription
+	var ok bool
+
+	subject := string(c.pa.subject)
+
+	if srv != nil {
+		genid = atomic.LoadUint64(&srv.sl.genid)
+	}
+
+	if genid == c.cache.genid && c.cache.subs != nil {
+		r, ok = c.cache.subs[subject]
+	} else {
+		// reset
+		c.cache.subs = make(map[string][]*subscription)
+		c.cache.genid = genid
+	}
+	if !ok {
+		r = srv.sl.Match(subject)
+		c.cache.subs[subject] = r
+	}
 
-	r := srv.sl.Match(string(c.pa.subject))
 	if len(r) <= 0 {
 		return
 	}
diff --git a/server/sublist.go b/server/sublist.go
index 5be67ace..2569a2a9 100644
--- a/server/sublist.go
+++ b/server/sublist.go
@@ -33,6 +33,7 @@ const slCacheMax = 1024
 // A Sublist stores and efficiently retrieves subscriptions.
 type Sublist struct {
 	sync.RWMutex
+	genid     uint64
 	matches   uint64
 	cacheHits uint64
 	inserts   uint64
@@ -128,9 +129,9 @@ func (s *Sublist) Insert(sub *subscription) error {
 	s.inserts++
 
 	s.addToCache(subject, sub)
+	atomic.AddUint64(&s.genid, 1)
 
 	s.Unlock()
-
 	return nil
 }
 
@@ -305,6 +306,7 @@ func (s *Sublist) Remove(sub *subscription) error {
 		}
 	}
 	s.removeFromCache(subject, sub)
+	atomic.AddUint64(&s.genid, 1)
 
 	return nil
 }