<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=us-ascii">
<meta name="Generator" content="Microsoft Word 14 (filtered medium)">
<title>Unexpected srrt in loopback</title>
<style><!--
/* Font Definitions */
@font-face
{font-family:SimSun;
panose-1:2 1 6 0 3 1 1 1 1 1;}
@font-face
{font-family:SimSun;
panose-1:2 1 6 0 3 1 1 1 1 1;}
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
@font-face
{font-family:Tahoma;
panose-1:2 11 6 4 3 5 4 4 2 4;}
@font-face
{font-family:"\@SimSun";
panose-1:2 1 6 0 3 1 1 1 1 1;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0in;
margin-bottom:.0001pt;
font-size:12.0pt;
font-family:SimSun;
mso-fareast-language:ZH-CN;}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:blue;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{mso-style-priority:99;
color:purple;
text-decoration:underline;}
p
{mso-style-priority:99;
mso-margin-top-alt:auto;
margin-right:0in;
mso-margin-bottom-alt:auto;
margin-left:0in;
font-size:12.0pt;
font-family:SimSun;
mso-fareast-language:ZH-CN;}
span.EmailStyle18
{mso-style-type:personal-reply;
color:black;}
.MsoChpDefault
{mso-style-type:export-only;
font-size:10.0pt;}
@page WordSection1
{size:8.5in 11.0in;
margin:1.0in 1.0in 1.0in 1.0in;}
div.WordSection1
{page:WordSection1;}
--></style><!--[if gte mso 9]><xml>
<o:shapedefaults v:ext="edit" spidmax="1026" />
</xml><![endif]--><!--[if gte mso 9]><xml>
<o:shapelayout v:ext="edit">
<o:idmap v:ext="edit" data="1" />
</o:shapelayout></xml><![endif]-->
</head>
<body lang="EN-US" link="blue" vlink="purple">
<div class="WordSection1">
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#002060">The network transit time over software loopback should be minimal, but network transit time isn’t the only thing which contributes to overall RTT.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#002060"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#002060">Sounds like your named process is struggling to keep up with 5000 QPS. Have you looked at the memory, CPU? Are you running with a single thread, or multiple
threads? Are you bumping into operating-system limits (which are, depending on platform, tunable in named.conf)? There could be a lot of reasons why named gets backed up in processing requests, and these aren’t necessarily evident from doing a simple dig against
an otherwise-idle named instance.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#002060"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#002060"> - Kevin<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:black"><o:p> </o:p></span></p>
<div>
<div style="border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in">
<p class="MsoNormal"><b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> bind-users-bounces@lists.isc.org [mailto:bind-users-bounces@lists.isc.org]
<b>On Behalf Of </b>???<br>
<b>Sent:</b> Tuesday, November 04, 2014 4:39 AM<br>
<b>To:</b> bind-users@lists.isc.org<br>
<b>Subject:</b> Unexpected srrt in loopback<o:p></o:p></span></p>
</div>
</div>
<p class="MsoNormal"><o:p> </o:p></p>
<p><span style="font-family:"Calibri","sans-serif"">Hi everyone, I try to set up an authentic bind server in the loopback address(127.0.0.1) in our recursive server of</span>
<a name=""><span style="font-family:"Calibri","sans-serif"">our</span></a> <span style="font-family:"Calibri","sans-serif"">
testbed for test reason. When I send a large number of junk queries(5000QPS), the srrt of loopback server in cash is unexpectedly large. Does anyone know the reason?</span>
<span style="font-family:"Calibri","sans-serif"">The</span> <span style="font-family:"Calibri","sans-serif"">
srrt is normal when I dig or</span> <span style="font-family:"Calibri","sans-serif"">
ping the loopback server by the way.</span><o:p></o:p></p>
<p><span style="font-family:"Calibri","sans-serif"">The dump_cache.db’s content:</span><o:p></o:p></p>
<p><span style="font-size:10.0pt;font-family:"Calibri","sans-serif"">; Address database dump</span><o:p></o:p></p>
<p><span style="font-size:10.0pt;font-family:"Calibri","sans-serif"">;</span><o:p></o:p></p>
<p><span style="font-size:10.0pt;font-family:"Calibri","sans-serif"">; 10.root-servers.net [v4 TTL 10744] [v6 TTL 86344] [v4 nxrrset] [v6 success]</span><o:p></o:p></p>
<p><span style="font-size:10.0pt;font-family:"Calibri","sans-serif"">; 240c:f:1:122::13 [srtt 212] [flags 00002000] [ttl 1746]</span><o:p></o:p></p>
<p><span style="font-size:10.0pt;font-family:"Calibri","sans-serif"">; 8.root-servers.net [v4 TTL 10744] [v6 TTL 86344] [v4 nxrrset] [v6 success]</span><o:p></o:p></p>
<p><span style="font-size:10.0pt;font-family:"Calibri","sans-serif"">; 240c:f:1:122::11 [srtt 744] [flags 00002000] [ttl 1746]</span><o:p></o:p></p>
<p><span style="font-size:10.0pt;font-family:"Calibri","sans-serif"">; 3.root-servers.net [v4 TTL 10744] [v6 TTL 86344] [v4 nxrrset] [v6 success]</span><o:p></o:p></p>
<p><span style="font-size:10.0pt;font-family:"Calibri","sans-serif"">; 240c:f:1:122::6 [srtt 171] [flags 00002000] [ttl 1746]</span><o:p></o:p></p>
<p><span style="font-size:10.0pt;font-family:"Calibri","sans-serif"">; 9.root-servers.net [v4 TTL 10744] [v6 TTL 86344] [v4 nxrrset] [v6 success]</span><o:p></o:p></p>
<p><span style="font-size:10.0pt;font-family:"Calibri","sans-serif"">; 240c:f:1:122::12 [srtt 44] [flags 00002000] [ttl 1746]</span><o:p></o:p></p>
<p><span style="font-size:10.0pt;font-family:"Calibri","sans-serif"">; 4.root-servers.net [v4 TTL 10744] [v6 TTL 86344] [v4 nxrrset] [v6 success]</span><o:p></o:p></p>
<p><span style="font-size:10.0pt;font-family:"Calibri","sans-serif"">; 240c:f:1:122::7 [srtt 64] [flags 00002000] [ttl 1746]</span><o:p></o:p></p>
<p><span style="font-size:10.0pt;font-family:"Calibri","sans-serif"">; 13.root-servers.net [v4 TTL 10744] [v6 TTL 86344] [v4 nxrrset] [v6 success]</span><o:p></o:p></p>
<p><span style="font-size:10.0pt;font-family:"Calibri","sans-serif"">; 240c:f:1:122::16 [srtt 26] [flags 00002000] [ttl 1746]</span><o:p></o:p></p>
<p><span style="font-size:10.0pt;font-family:"Calibri","sans-serif"">; 5.root-servers.net [v4 TTL 10744] [v6 TTL 86344] [v4 nxrrset] [v6 success]</span><o:p></o:p></p>
<p><span style="font-size:10.0pt;font-family:"Calibri","sans-serif"">; 240c:f:1:122::8 [srtt 29] [flags 00002000] [ttl 1746]</span><o:p></o:p></p>
<p><span style="font-size:10.0pt;font-family:"Calibri","sans-serif"">; 12.root-servers.net [v4 TTL 10744] [v6 TTL 86344] [v4 nxrrset] [v6 success]</span><o:p></o:p></p>
<p><span style="font-size:10.0pt;font-family:"Calibri","sans-serif"">; 240c:f:1:122::15 [srtt 2054] [flags 00002000] [ttl 1746]</span><o:p></o:p></p>
<p><span style="font-size:10.0pt;font-family:"Calibri","sans-serif"">; 6.root-servers.net [v4 TTL 10744] [v6 TTL 86344] [v4 nxrrset] [v6 success]</span><o:p></o:p></p>
<p><span style="font-size:10.0pt;font-family:"Calibri","sans-serif"">; 240c:f:1:122::9 [srtt 663] [flags 00002000] [ttl 1746]</span><o:p></o:p></p>
<p><span style="font-size:10.0pt;font-family:"Calibri","sans-serif"">; 1.root-servers.net [v4 TTL 10744] [v6 TTL 86344] [v4 nxrrset] [v6 success]</span><o:p></o:p></p>
<p><span style="font-size:10.0pt;font-family:"Calibri","sans-serif"">; 240c:f:1:122::2 [srtt 550] [flags 00002000] [ttl 1746]</span><o:p></o:p></p>
<p><span style="font-size:10.0pt;font-family:"Calibri","sans-serif"">; 11.root-servers.net [v4 TTL 10744] [v6 TTL 86344] [v4 nxrrset] [v6 success]</span><o:p></o:p></p>
<p><span style="font-size:10.0pt;font-family:"Calibri","sans-serif"">; 240c:f:1:122::14 [srtt 44] [flags 00002000] [ttl 1746]</span><o:p></o:p></p>
<p><span style="font-size:10.0pt;font-family:"Calibri","sans-serif"">; 7.root-servers.net [v4 TTL 10744] [v6 TTL 86344] [v4 nxrrset] [v6 success]</span><o:p></o:p></p>
<p><span style="font-size:10.0pt;font-family:"Calibri","sans-serif"">; 240c:f:1:122::10 [srtt 918] [flags 00002000] [ttl 1746]</span><o:p></o:p></p>
<p><span style="font-size:10.0pt;font-family:"Calibri","sans-serif"">; 2.root-servers.net [v4 TTL 10744] [v6 TTL 86344] [v4 nxrrset] [v6 success]</span><o:p></o:p></p>
<p><span style="font-size:10.0pt;font-family:"Calibri","sans-serif"">; 240c:f:1:122::5 [srtt 360] [flags 00002000] [ttl 1746]</span><o:p></o:p></p>
<p><span style="font-size:10.0pt;font-family:"Calibri","sans-serif"">; Unassociated entries</span><o:p></o:p></p>
<p><span style="font-size:10.0pt;font-family:"Calibri","sans-serif"">;</span><o:p></o:p></p>
<p><span style="font-size:10.0pt;font-family:"Calibri","sans-serif"">; ::1 [srtt 689] [flags 00002000] [ttl 1745]</span><o:p></o:p></p>
<p class="MsoNormal" style="margin-bottom:12.0pt"><br>
<br>
<br>
<br>
<br>
<br>
<o:p></o:p></p>
<p><span style="font-size:10.0pt;font-family:"Calibri","sans-serif"">Best Regards</span><o:p></o:p></p>
<p><span style="font-size:10.0pt;font-family:"Calibri","sans-serif"">Runxia Wan</span><o:p></o:p></p>
<p><br>
<span style="font-size:10.0pt;color:#333333">---------------<br>
Runxia Wan(Brian)</span><o:p></o:p></p>
<p><span style="font-size:10.0pt;color:#333333">Research Engineer<br>
BII Lab</span><o:p></o:p></p>
<p><span style="font-size:10.0pt;color:#333333">Beijing Internet Institute(BII)</span><o:p></o:p></p>
<p><span style="font-size:10.0pt;color:black"><a href="mailto:rxwan@biigroup.cn">rxwan@biigroup.cn</a></span><o:p></o:p></p>
</div>
</body>
</html>