From 525be5b8a7a260a36c53bba07fa9230626c8acf6 Mon Sep 17 00:00:00 2001
From: Dmitry Vyukov <dvyukov@google.com>
Date: Mon, 30 Jan 2017 15:40:04 +0100
Subject: manager: don't recalculate dynamic priorities too often

Recalculating dynamic priorities requires deserializing all programs,
and that is slow. So do it at most once per 30 mins and don't hold
the mutex during prio calculation.
---
 syz-manager/manager.go | 34 ++++++++++++++++++++++++----------
 1 file changed, 24 insertions(+), 10 deletions(-)

diff --git a/syz-manager/manager.go b/syz-manager/manager.go
index 5b7ee98ba..2da12cd33 100644
--- a/syz-manager/manager.go
+++ b/syz-manager/manager.go
@@ -50,6 +50,7 @@ type Manager struct {
 	corpusDB     *db.DB
 	startTime    time.Time
 	firstConnect time.Time
+	lastPrioCalc time.Time
 	fuzzingTime  time.Duration
 	stats        map[string]uint64
 	crashTypes   map[string]bool
@@ -592,16 +593,6 @@ func (mgr *Manager) minimizeCorpus() {
 		mgr.corpus = newCorpus
 	}
 
-	var corpus []*prog.Prog
-	for _, inp := range mgr.corpus {
-		p, err := prog.Deserialize(inp.Prog)
-		if err != nil {
-			panic(err)
-		}
-		corpus = append(corpus, p)
-	}
-	mgr.prios = prog.CalculatePriorities(corpus)
-
 	// Don't minimize persistent corpus until fuzzers have triaged all inputs from it.
 	if len(mgr.candidates) == 0 {
 		for key := range mgr.corpusDB.Records {
@@ -631,6 +622,29 @@ func (mgr *Manager) Connect(a *ConnectArgs, r *ConnectRes) error {
 	mgr.fuzzers[a.Name] = f
 	mgr.minimizeCorpus()
 
+	if mgr.prios == nil || time.Since(mgr.lastPrioCalc) > 30*time.Minute {
+		// Deserializing all programs is slow, so we do it episodically and without holding the mutex.
+		mgr.lastPrioCalc = time.Now()
+		inputs := make([][]byte, 0, len(mgr.corpus))
+		for _, inp := range mgr.corpus {
+			inputs = append(inputs, inp.Prog)
+		}
+		mgr.mu.Unlock()
+
+		corpus := make([]*prog.Prog, 0, len(inputs))
+		for _, inp := range inputs {
+			p, err := prog.Deserialize(inp)
+			if err != nil {
+				panic(err)
+			}
+			corpus = append(corpus, p)
+		}
+		prios := prog.CalculatePriorities(corpus)
+
+		mgr.mu.Lock()
+		mgr.prios = prios
+	}
+
 	f.inputs = nil
 	for _, inp := range mgr.corpus {
 		r.Inputs = append(r.Inputs, inp)
-- 
cgit mrf-deployment