<html><head></head><body><div style="color:#000; background-color:#fff; font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, Sans-Serif;font-size:13px"><div id="yiv8236688825yui_3_16_0_1_1454947889432_5904" class="">Hi,</div><div id="yiv8236688825yui_3_16_0_1_1454947889432_5926" class="" style="margin: 0px; padding: 0px; border: 0px; font-family: Helvetica; font-size: 12px;"><b class="" id="yui_3_16_0_1_1454947889432_53459"><br id="yui_3_16_0_1_1454947889432_53461" class=""></b></div><div id="yiv8236688825yui_3_16_0_1_1454947889432_5926" class="" style="margin: 0px; padding: 0px; border: 0px;"><span id="yiv8236688825yui_3_16_0_1_1454947889432_7009" class=""><font face="Helvetica" id="yiv8236688825yui_3_16_0_1_1454947889432_7010" class=""><span id="yiv8236688825yui_3_16_0_1_1454947889432_7011" style="font-size: 12px;" class="">I was doing load testing using openssl external session caching feature and was facing some issues. Details are as below:</span></font></span></div><div id="yiv8236688825yui_3_16_0_1_1454947889432_5926" class="" style="margin: 0px; padding: 0px; border: 0px;"><font face="Helvetica" id="yui_3_16_0_1_1454947889432_53468" class=""><span style="font-size: 12px;" id="yui_3_16_0_1_1454947889432_53470" class=""><br id="yui_3_16_0_1_1454947889432_53472" class=""></span></font></div><div id="yiv8236688825yui_3_16_0_1_1454947889432_5926" class="" style="margin: 0px; padding: 0px; border: 0px; font-family: Helvetica; font-size: 12px;"><b id="yiv8236688825yui_3_16_0_1_1454947889432_5928" class="">Test setup</b></div><div id="yiv8236688825yui_3_16_0_1_1454947889432_5930" class="" style="margin: 0px; padding: 0px; border: 0px; font-family: Helvetica; font-size: 12px;"><br id="yiv8236688825yui_3_16_0_1_1454947889432_5932" class=""></div><div id="yiv8236688825yui_3_16_0_1_1454947889432_5934" class="" style="margin: 0px; padding: 0px; border: 0px; font-family: Helvetica; font-size: 12px;">I used nginx-1.0.10 and tested it for shared memory cache. Client sends around 200 Requests/sec and 50% of requests reuses ssl session.</div><div id="yiv8236688825yui_3_16_0_1_1454947889432_5936" class="" style="margin: 0px; padding: 0px; border: 0px; font-family: Helvetica; font-size: 12px;"><br id="yiv8236688825yui_3_16_0_1_1454947889432_5938" class=""></div><div id="yiv8236688825yui_3_16_0_1_1454947889432_5940" class="" style="margin: 0px; padding: 0px; border: 0px; font-family: Helvetica; font-size: 12px;">OpenSSL version used is <span id="yiv8236688825yui_3_16_0_1_1454947889432_5942" class="" style="margin: 0px; padding: 0px; border: 0px; font-family: Menlo; font-size: 11px;">OpenSSL 1.0.1e-fips 11 Feb 2013.</span></div><div id="yiv8236688825yui_3_16_0_1_1454947889432_5944" class="" style="margin: 0px; padding: 0px; border: 0px; font-family: Helvetica; font-size: 12px;"><br id="yiv8236688825yui_3_16_0_1_1454947889432_5946" class=""></div><div id="yiv8236688825yui_3_16_0_1_1454947889432_5948" class="" style="margin: 0px; padding: 0px; border: 0px; font-family: Helvetica; font-size: 12px;">The operational mode used for session caching is as below:</div><div id="yiv8236688825yui_3_16_0_1_1454947889432_5950" class="" style="margin: 0px; padding: 0px; border: 0px; font-family: Helvetica; font-size: 12px;"><br id="yiv8236688825yui_3_16_0_1_1454947889432_5952" class=""></div><div id="yiv8236688825yui_3_16_0_1_1454947889432_5954" class="" style="margin: 0px; padding: 0px; border: 0px; font-family: Helvetica; font-size: 12px;"><i id="yiv8236688825yui_3_16_0_1_1454947889432_5956" class="" style="font-family: arial, sans-serif;">SSL_CTX_set_session_cache_ mode(ssl->ctx, </i><span id="yiv8236688825yui_3_16_0_1_1454947889432_5960" class="" style="margin: 0px; padding: 0px; border: 0px; font-family: arial, sans-serif;">SSL_SESS_CACHE_ SERVER | </span><span id="yiv8236688825yui_3_16_0_1_1454947889432_5964" class="" style="margin: 0px; padding: 0px; border: 0px; font-family: arial, sans-serif;">SSL_SESS_CACHE_NO_INTERNAL</span><i id="yiv8236688825yui_3_16_0_1_1454947889432_5966" class="" style="font-family: arial, sans-serif;">);</i></div><div id="yiv8236688825yui_3_16_0_1_1454947889432_5954" class="" style="margin: 0px; padding: 0px; border: 0px; font-family: Helvetica; font-size: 12px;"><i class="" style="font-family: arial, sans-serif;" id="yui_3_16_0_1_1454947889432_53494"><br id="yui_3_16_0_1_1454947889432_53496" class=""></i></div><div id="yiv8236688825yui_3_16_0_1_1454947889432_5954" class="" dir="ltr" style="margin: 0px; padding: 0px; border: 0px; font-family: Helvetica; font-size: 12px;"><span id="yiv8236688825yui_3_16_0_1_1454947889432_7208" class="" style="font-family: arial, sans-serif;">SSL_SESS_CACHE_NO_INTERNAL is to ensure that OpenSSL does not store sessions internally and do any internal lookups .</span><br id="yui_3_16_0_1_1454947889432_53500" class=""></div><div id="yiv8236688825yui_3_16_0_1_1454947889432_5968" class="" style="margin: 0px; padding: 0px; border: 0px; font-family: Helvetica; font-size: 12px;"><i id="yiv8236688825yui_3_16_0_1_1454947889432_5970" class="" style="font-family: arial, sans-serif;"><br id="yiv8236688825yui_3_16_0_1_1454947889432_5972" class=""></i></div><div id="yiv8236688825yui_3_16_0_1_1454947889432_5974" class="" style="margin: 0px; padding: 0px; border: 0px; font-family: Helvetica; font-size: 12px;"><span id="yiv8236688825yui_3_16_0_1_1454947889432_5976" class="" style="margin: 0px; padding: 0px; border: 0px; font-family: arial, sans-serif;"><b id="yiv8236688825yui_3_16_0_1_1454947889432_5978" class="">Results:</b></span></div><div id="yiv8236688825yui_3_16_0_1_1454947889432_5986" class="" style="margin-top: 1em; margin-bottom: 1em; border: 0px; line-height: normal; font-family: Helvetica; font-size: 12px; text-align: center; clear: both;"></div><div id="yiv8236688825yui_3_16_0_1_1454947889432_5988" class="" dir="ltr" style="margin: 0px; padding: 0px; border: 0px; color: rgb(34, 34, 34); font-family: Arial, Helvetica, sans-serif;"><font color="#000000" id="yiv8236688825yui_3_16_0_1_1454947889432_5990" class="" style="margin: 0px; padding: 0px; border: 0px; font-family: arial, sans-serif;"><span id="yiv8236688825yui_3_16_0_1_1454947889432_5992" class="" style="margin: 0px; padding: 0px; border: 0px; font-size: 12px;">I am seeing increase in response times and it looks like an issue with OpenSSL. As you can see, the connect time increases over time from 30 ms (t = 100 s) to 120 ms (at t = 500 s). Requests per sec remains the same over this time . </span></font></div><div id="yiv8236688825yui_3_16_0_1_1454947889432_5988" class="" dir="ltr" style="margin: 0px; padding: 0px; border: 0px; color: rgb(34, 34, 34); font-family: Arial, Helvetica, sans-serif;"><font color="#000000" class="" style="margin: 0px; padding: 0px; border: 0px; font-family: arial, sans-serif;"><span class="" style="margin: 0px; padding: 0px; border: 0px; font-size: 12px;"><br></span></font></div><div id="yiv8236688825yui_3_16_0_1_1454947889432_5988" class="" dir="ltr" style="margin: 0px; padding: 0px; border: 0px; color: rgb(34, 34, 34); font-family: Arial, Helvetica, sans-serif;"><font color="#000000" class="" style="margin: 0px; padding: 0px; border: 0px; font-family: arial, sans-serif;" id="yui_3_16_0_1_1454947889432_55187"><span class="" style="margin: 0px; padding: 0px; border: 0px; font-size: 12px;" id="yui_3_16_0_1_1454947889432_55186">I suspect the issue is with OpenSSL framework which does some operations over large lists. </span></font></div><div id="yiv8236688825yui_3_16_0_1_1454947889432_5988" class="" dir="ltr" style="margin: 0px; padding: 0px; border: 0px; color: rgb(34, 34, 34); font-family: Arial, Helvetica, sans-serif;"><font color="#000000" class="" style="margin: 0px; padding: 0px; border: 0px; font-family: arial, sans-serif;" id="yui_3_16_0_1_1454947889432_53513"><span class="" style="margin: 0px; padding: 0px; border: 0px; font-size: 12px;" id="yui_3_16_0_1_1454947889432_53515"><br id="yui_3_16_0_1_1454947889432_53517" class=""></span></font></div><div id="yiv8236688825yui_3_16_0_1_1454947889432_5988" class="" dir="ltr" style="margin: 0px; padding: 0px; border: 0px; color: rgb(34, 34, 34); font-family: Arial, Helvetica, sans-serif;"><font color="#000000" class="" id="yui_3_16_0_1_1454947889432_53291" style="margin: 0px; padding: 0px; border: 0px; font-family: arial, sans-serif;"><span class="" id="yui_3_16_0_1_1454947889432_53290" style="margin: 0px; padding: 0px; border: 0px; font-size: 12px;">Please find attached the connect and request time graph for reference.</span></font></div><div id="yiv8236688825yui_3_16_0_1_1454947889432_5994" class="" dir="ltr" style="margin: 0px; padding: 0px; border: 0px; color: rgb(34, 34, 34); font-family: Arial, Helvetica, sans-serif;"><br id="yiv8236688825yui_3_16_0_1_1454947889432_11581" class=""></div><div id="yiv8236688825yui_3_16_0_1_1454947889432_6036" class="" style="margin: 0px; padding: 0px; border: 0px; font-family: Arial, Helvetica, sans-serif; font-size: 12px;"><font face="arial, sans-serif" id="yiv8236688825yui_3_16_0_1_1454947889432_6038" class="" style="margin: 0px; padding: 0px; border: 0px;">Any feed back would be appreciated.</font></div><div id="yiv8236688825yui_3_16_0_1_1454947889432_6040" class="" style="margin: 0px; padding: 0px; border: 0px; font-family: Helvetica; font-size: 12px;"><span id="yiv8236688825yui_3_16_0_1_1454947889432_6042" class="" style="margin: 0px; padding: 0px; border: 0px; font-family: arial, sans-serif;"><br id="yiv8236688825yui_3_16_0_1_1454947889432_6044" class=""></span></div><div id="yiv8236688825yui_3_16_0_1_1454947889432_6046" class="" style="margin: 0px; padding: 0px; border: 0px; font-family: Helvetica; font-size: 12px;"><span id="yiv8236688825yui_3_16_0_1_1454947889432_6048" class="" style="margin: 0px; padding: 0px; border: 0px; font-family: arial, sans-serif;">Thanks,</span></div><div dir="ltr" id="yiv8236688825yui_3_16_0_1_1454947889432_6050" class="" style="margin: 0px; padding: 0px; border: 0px; font-family: Helvetica; font-size: 12px;"><span id="yiv8236688825yui_3_16_0_1_1454947889432_6052" class="" style="margin: 0px; padding: 0px; border: 0px; font-family: arial, sans-serif;">Sreekanth</span></div></div></body></html>