From f8ad2ac3e252108ccfedd115eb3009a5a7d77106 Mon Sep 17 00:00:00 2001
From: Jakob Unterwurzacher
Date: Sun, 17 May 2020 21:37:36 +0200
Subject: dircache: increase cache size & lifetime

Looking at the dircache debug output, we see
that a "git status" workload has a very bad
cache hit rate because the entries expire or
get evicted before they can be reused.

Increase both cache size and lifetime for
a 4x speedup:

Before: 75s
After:  17s

https://github.com/rfjakob/gocryptfs/issues/410
---
 internal/fusefrontend/dircache.go | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

(limited to 'internal/fusefrontend')

diff --git a/internal/fusefrontend/dircache.go b/internal/fusefrontend/dircache.go
index 718e5b2..d6ec52c 100644
--- a/internal/fusefrontend/dircache.go
+++ b/internal/fusefrontend/dircache.go
@@ -12,11 +12,11 @@ import (
 )
 
 const (
-	// Number of entries in the dirCache. Three entries work well for two
-	// (probably also three) parallel tar extracts (hit rate around 92%).
+	// Number of entries in the dirCache.
+	// 20 entries work well for "git stat" on a small git repo on sshfs.
 	// Keep in sync with test_helpers.maxCacheFds !
 	// TODO: How to share this constant without causing an import cycle?
-	dirCacheSize = 3
+	dirCacheSize = 20
 	// Enable Lookup/Store/Clear debug messages
 	enableDebugMessages = false
 	// Enable hit rate statistics printing
@@ -151,7 +151,7 @@ func (d *dirCacheStruct) Lookup(dirRelPath string) (fd int, iv []byte) {
 // expireThread is started on the first Lookup()
 func (d *dirCacheStruct) expireThread() {
 	for {
-		time.Sleep(1 * time.Second)
+		time.Sleep(60 * time.Second)
 		d.Clear()
 		if enableStats {
 			d.Lock()
-- 
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