1 files changed, 55 insertions, 0 deletions
diff --git a/lib/gitlab_metrics.rb b/lib/gitlab_metrics.rb
new file mode 100644
index 0000000..7bf07a5
--- /dev/null
+++ b/lib/gitlab_metrics.rb
@@ -0,0 +1,55 @@
+require 'logger'
+require_relative 'gitlab_config'
+
+module GitlabMetrics
+  module System
+    # THREAD_CPUTIME is not supported on OS X
+    if Process.const_defined?(:CLOCK_THREAD_CPUTIME_ID)
+      def self.cpu_time
+        Process.
+          clock_gettime(Process::CLOCK_THREAD_CPUTIME_ID, :millisecond)
+      end
+    else
+      def self.cpu_time
+        Process.
+          clock_gettime(Process::CLOCK_PROCESS_CPUTIME_ID, :millisecond)
+      end
+    end
+
+    # Returns the current monotonic clock time in a given precision.
+    #
+    # Returns the time as a Fixnum.
+    def self.monotonic_time
+      Process.clock_gettime(Process::CLOCK_MONOTONIC, :millisecond)
+    end
+  end
+
+  def self.logger
+    @logger ||= Logger.new(GitlabConfig.new.metrics_log_file)
+  end
+
+  # Measures the execution time of a block.
+  #
+  # Example:
+  #
+  #     GitlabMetrics.measure(:find_by_username_duration) do
+  #       User.find_by_username(some_username)
+  #     end
+  #
+  # name - The name of the field to store the execution time in.
+  #
+  # Returns the value yielded by the supplied block.
+  def self.measure(name)
+    start_real = System.monotonic_time
+    start_cpu = System.cpu_time
+
+    retval = yield
+
+    real_time = System.monotonic_time - start_real
+    cpu_time = System.cpu_time - start_cpu
+
+    logger.debug { "name=#{name.inspect} wall_time=#{real_time.inspect} cpu_time=#{cpu_time.inspect}" }
+
+    retval
+  end
+end