<html><body><div style="color:#000; background-color:#fff; font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:14pt"><div class="" style=""><span class="" style=""><br style=""></span></div><div style="color: rgb(0, 0, 0); font-size: 19px; font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; background-color: transparent; font-style: normal" class=""><span class="" style="">Hi Evan,</span></div><div style="color: rgb(0, 0, 0); font-size: 19px; font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; background-color: transparent; font-style: normal" class=""><br class="" style=""></div><div style="color: rgb(0, 0, 0); font-size: 19px; font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; background-color: transparent; font-style: normal;" class="">Thanks for your response!</div><div style="color:
rgb(0, 0, 0); font-size: 19px; font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; background-color: transparent; font-style: normal" class="">It's 9.9.4b1. Adjusting the number of listeners only helped a little bit.</div><div style="color: rgb(0, 0, 0); font-size: 19px; font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; background-color: transparent; font-style: normal" class=""><a href="https://www.dropbox.com/s/rinosv66qnxzsl7/large_recv_buffer.jpeg" class="" style="">large_recv_buffer.jpeg</a><br class="" style=""></div><div style="width:450px; font-family: 'Georgia', 'Times', 'Times New Roman', 'serif';" contenteditable="false" id="enhancrCard_0" class="link-enhancr-attachment link-enhancr-element"><table class="link-enhancr-element" cellspacing="0" cellpadding="0" style="width:450px; height:170px; position: relative; margin-top:5px; margin-bottom: 5px; display:
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1px; background-color: #e5e5e5;"><div class="link-enhancr-element" style="height: 1px; background-color: #e5e5e5;"></div></td></tr></tbody></table></div><div style="color: rgb(0, 0, 0); font-size: 19px; font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; background-color: transparent; font-style: normal;" class=""><br></div><div style="color: rgb(0, 0, 0); font-size: 19px; font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; background-color: transparent; font-style: normal" class="">The concern I have it that the drop rate increases linearly with steep slope on RHEL 6.4. Do we need to adjust the number of workers as well? How do we determine a good combination of number of listeners and workers besides running extensive tests to see what gives us the best performance?</div><div style="color: rgb(0, 0, 0); font-size: 19px; font-family: HelveticaNeue, 'Helvetica Neue',
Helvetica, Arial, 'Lucida Grande', sans-serif; background-color: transparent; font-style: normal" class=""><br class="" style=""></div><div style="color: rgb(0, 0, 0); font-size: 19px; font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; background-color: transparent; font-style: normal" class="">The kernel we are running already has the "lockless UDP" changes: <a href="https://access.redhat.com/site/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/6.1_Technical_Notes/kernel.html" style="font-family: Consolas; font-size: medium; background-color: rgb(255, 255, 255)" class="">https://access.redhat.com/site/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/6.1_Technical_Notes/kernel.html</a></div><div class="" style=""><br class="" style=""></div><div class="" style=""><br class="" style=""></div><div class="yahoo_quoted" style="display: block;"> <div style="font-family: HelveticaNeue, Helvetica Neue,
Helvetica, Arial, Lucida Grande, sans-serif; font-size: 14pt" class=""> <div style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 12pt" class=""> <div dir="ltr" class="" style=""> <font size="2" face="Arial" class="" style=""> On Tuesday, April 22, 2014 3:05 PM, Evan Hunt <each@isc.org> wrote:<br class="" style=""> </font> </div> <blockquote style="" class=""> <div class="" style="">On Tue, Apr 22, 2014 at 02:40:08PM -0700, Shawn Zhou wrote:<div class="" id="yqtfd93551" style=""><br clear="none" class="" style="">> Our performance tests show that ISC BIND (authoritative only setup)<br clear="none" class="" style="">> doesn't perform well on RHEL 6.4 in comparison with FreeBSD<br clear="none" class="" style="">> 7:?bind_perf.png</div><br clear="none" class="" style=""><br clear="none" class="" style="">You didn't specify which version of BIND, but I know that BIND 9.9 and<br
clear="none" class="" style="">higher, when running on Linux, is sensitive to the number of threads<br clear="none" class="" style="">listening for incoming UDP connections. You can adjust this via the -U<br clear="none" class="" style="">command line option: If you have 8 processors, I'd try it at -U 4, -U 5,<br clear="none" class="" style="">-U 6 and -U 7 and see where the peak performance was found.<br clear="none" class="" style=""><br clear="none" class="" style="">Older linux kernels had a problematic UDP stack that caused a big<br clear="none" class="" style="">performance drop relative to BSD or Solaris, essentially reducing it<br clear="none" class="" style="">to single-thread performance. I believe all the major Linux distributions<br clear="none" class="" style="">have switched to lockless UDP by now, but it might be worth checking out.<br clear="none" class="" style=""><br clear="none" class="" style="">-- <br clear="none" class=""
style="">Evan Hunt -- <a shape="rect" ymailto="mailto:each@isc.org" href="mailto:each@isc.org" class="" style="">each@isc.org</a><br clear="none" class="" style="">Internet Systems Consortium, Inc.<div class="" id="yqtfd02160" style=""><br clear="none" class="" style=""></div><br class="" style=""><br class="" style=""></div> </blockquote> </div> </div> </div> </div></body></html>