From ac5be236c64c3e0f4294a84e4e37b6e1c3c07220 Mon Sep 17 00:00:00 2001
From: Tom Werner <tom@tom.local>
Date: Tue, 4 Sep 2007 18:42:29 -0700
Subject: [PATCH] optimize timeline since logs rely on it heavily

---
 bin/god               |  2 ++
 lib/god/timeline.rb   | 19 ++++++++++++++++++-
 test/test_timeline.rb | 12 ++++++++++++
 3 files changed, 32 insertions(+), 1 deletion(-)

diff --git a/bin/god b/bin/god
index 0e96c9b..a95a639 100755
--- a/bin/god
+++ b/bin/god
@@ -14,6 +14,7 @@ Usage: god [command] [options]
 
   Commands:
     start <watch or group name>
+    restart <watch or group name>
     stop <watch or group name>
     monitor <watch or group name>
     unmonitor <watch or group name>
@@ -146,6 +147,7 @@ elsif command = ARGV[0]
   
     begin
       puts "Sending '#{command}' command"
+      puts "This may take a few seconds depending on the grace periods assigned to your watches"
     
       # send command
       watches = server.control(name, command)
diff --git a/lib/god/timeline.rb b/lib/god/timeline.rb
index 2445071..12c1904 100644
--- a/lib/god/timeline.rb
+++ b/lib/god/timeline.rb
@@ -6,9 +6,26 @@ module God
         @max_size = max_size
       end
       
+      # Push a value onto the Timeline
+      # 
+      # Implementation explanation:
+      # A performance optimization appears here to speed up the push time.
+      # In essence, the code does this:
+      #
+      #   def push(val)
+      #     super(val)
+      #     shift if size > @max_size
+      #   end
+      #
+      # But that's super slow due to the shift, so we resort to reverse! and pop
+      # which gives us a 2x speedup with 100 elements and a 6x speedup with 1000
       def push(val)
+        if (size + 1) > @max_size
+          reverse!
+          pop
+          reverse!
+        end
         super(val)
-        shift if size > @max_size
       end
       
       def <<(val)
diff --git a/test/test_timeline.rb b/test/test_timeline.rb
index 1c0862d..c714f98 100644
--- a/test/test_timeline.rb
+++ b/test/test_timeline.rb
@@ -21,4 +21,16 @@ class TestTimeline < Test::Unit::TestCase
     @timeline.push(1)
     assert_equal [], @timeline.clear
   end
+  
+  # def test_benchmark
+  #   require 'benchmark'
+  # 
+  #   count = 1_000_000
+  # 
+  #   t = Timeline.new(10)
+  # 
+  #   Benchmark.bmbm do |x|
+  #     x.report("go") { count.times { t.push(5) } }
+  #   end
+  # end
 end
-- 
2.11.4.GIT