From 4c6b1fc23c72dcde5456865103945ce7f228bfef Mon Sep 17 00:00:00 2001
From: Ryan Cobb <rcobb@gitlab.com>
Date: Tue, 4 Jun 2019 10:04:36 -0600
Subject: Add comment to clarify system proc stat field

---
 lib/gitlab/metrics/system.rb | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/lib/gitlab/metrics/system.rb b/lib/gitlab/metrics/system.rb
index 81bd799bd1e..33c0de91c11 100644
--- a/lib/gitlab/metrics/system.rb
+++ b/lib/gitlab/metrics/system.rb
@@ -35,6 +35,8 @@ module Gitlab
         def self.process_start_time
           fields = File.read('/proc/self/stat').split
 
+          # fields[21] is linux proc stat field "(22) starttime".
+          # The value is expressed in clock ticks, divide by clock ticks for seconds.
           ( fields[21].to_i || 0 ) / clk_tck
         end
       else
-- 
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