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authorEric Wong <e@80x24.org>2015-05-17 01:26:35 +0000
committerEric Wong <e@80x24.org>2015-05-17 01:36:20 +0000
commitf58942d2a238128d850384d16067811f8415d43f (patch)
tree66090578ff49a8f0050628c24e0e2fa9b465636d /lib
parent544243e0a14d0d507d0bd0fa34c41861486788e4 (diff)
downloaddtas-f58942d2a238128d850384d16067811f8415d43f.tar.gz
The monotonic clock is immune to stepping adjustments so it is
more suitable for tracking elapsed time differences.
Process.clock_gettime also generates less garbage on 64-bit systems
due to the use of Flonum.
Diffstat (limited to 'lib')
-rw-r--r--lib/dtas.rb12
-rw-r--r--lib/dtas/process.rb2
2 files changed, 13 insertions, 1 deletions
diff --git a/lib/dtas.rb b/lib/dtas.rb
index 9fc7253..f11d549 100644
--- a/lib/dtas.rb
+++ b/lib/dtas.rb
@@ -1,6 +1,18 @@
 # Copyright (C) 2013-2015 all contributors <dtas-all@nongnu.org>
 # License: GPLv3 or later (https://www.gnu.org/licenses/gpl-3.0.txt)
 module DTAS # :nodoc:
+  # try to use the monotonic clock in Ruby >= 2.1, it is immune to clock
+  # offset adjustments and generates less garbage (Float vs Time object)
+  begin
+    ::Process.clock_gettime(::Process::CLOCK_MONOTONIC)
+    def self.now
+      ::Process.clock_gettime(::Process::CLOCK_MONOTONIC)
+    end
+  rescue NameError, NoMethodError
+    def self.now # Ruby <= 2.0
+      Time.now.to_f
+    end
+  end
 end
 
 require_relative 'dtas/compat_onenine'
diff --git a/lib/dtas/process.rb b/lib/dtas/process.rb
index 5be107f..8c5e8e9 100644
--- a/lib/dtas/process.rb
+++ b/lib/dtas/process.rb
@@ -51,7 +51,7 @@ module DTAS::Process # :nodoc:
 
     pid = spawn(env, cmd, opts)
     warn [ :spawn, pid, cmd ].inspect if $DEBUG
-    @spawn_at = Time.now.to_f
+    @spawn_at = DTAS.now
     PIDS[pid] = self
     pid
   end