Add test-lru.rb to utils.

This is a program useful to evaluate the Redis LRU algorithm behavior.

Add test-lru.rb to utils.
This is a program useful to evaluate the Redis LRU algorithm behavior.
fd70c68c · antirez · 24c35024 · fd70c68c · fd70c68c
Commit fd70c68c authored Mar 21, 2014 by antirez
--- a/utils/lru/README
+++ b/utils/lru/README
+The test-lru.rb program can be used in order to check the behavior of the
+Redis approximated LRU algorithm against the theoretical output of true
+LRU algorithm.
+
+In order to use the program you need to recompile Redis setting the define
+REDIS_LRU_CLOCK_RESOLUTION to 1, by editing redis.h.
+This allows to execute the program in a fast way since the 1 ms resolution
+is enough for all the objects to have a different enough time stamp during
+the test.
+
+The program is executed like this:
+
+    ruby test-lru.rb > /tmp/lru.html
--- a/utils/lru/test-lru.rb
+++ b/utils/lru/test-lru.rb
+require 'rubygems'
+require 'redis'
+
+r = Redis.new
+r.config("SET","maxmemory","2000000")
+r.config("SET","maxmemory-policy","allkeys-lru")
+r.config("SET","maxmemory-samples",5)
+r.config("RESETSTAT")
+r.flushall
+
+puts <<EOF
+<html>
+<body>
+<style>
+.box {
+    width:5px;
+    height:5px;
+    float:left;
+    margin: 1px;
+}
+
+.old {
+    border: 1px black solid;
+}
+
+.new {
+    border: 1px green solid;
+}
+
+.ex {
+    background-color: #666;
+}
+</style>
+<pre>
+EOF
+
+# Fill
+oldsize = r.dbsize
+id = 0
+while true
+    id += 1
+    r.set(id,"foo")
+    newsize = r.dbsize
+    break if newsize == oldsize
+    oldsize = newsize
+end
+
+inserted = r.dbsize
+first_set_max_id = id
+puts "#{r.dbsize} keys inserted"
+
+# Access keys sequencially
+
+puts "Access keys sequencially"
+(1..first_set_max_id).each{|id|
+    r.get(id)
+#    sleep 0.001
+}
+
+# Insert more 50% keys. We expect that the new keys
+half = inserted/2
+puts "Insert enough keys to evict half the keys we inserted"
+add = 0
+while true
+    add += 1
+    id += 1
+    r.set(id,"foo")
+    break if r.info['evicted_keys'].to_i >= half
+end
+
+puts "#{add} additional keys added."
+puts "#{r.dbsize} keys in DB"
+
+# Check if evicted keys respect LRU
+# We consider errors from 1 to N progressively more serious as they violate
+# more the access pattern.
+
+errors = 0
+e = 1
+edecr = 1.0/(first_set_max_id/2)
+(1..(first_set_max_id/2)).each{|id|
+    e -= edecr if e > 0
+    e = 0 if e < 0
+    if r.exists(id)
+        errors += e
+    end
+}
+
+puts "#{errors} errors!"
+puts "</pre>"
+
+# Generate the graphical representation
+(1..id).each{|id|
+    # Mark first set and added items in a different way.
+    c = "box"
+    if id <= first_set_max_id
+        c << " old"
+    else
+        c << " new"
+    end
+
+    # Add class if exists
+    c << " ex" if r.exists(id)
+    puts "<div class=\"#{c}\"></div>"
+}
+
+# Close HTML page
+
+puts <<EOF
+</body>
+</html>
+EOF