<html><head><meta http-equiv="Content-Type" content="text/html charset=us-ascii"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">Hi Wenqin,<div class=""><br class=""></div><div class="">It may be because the probe is busy doing other things. We noticed a high interval between the scheduling and the actual measurement of one-off measurements on busy probes in <a href="http://conferences.sigcomm.org/imc/2015/papers/p437.pdf" class="">http://conferences.sigcomm.org/imc/2015/papers/p437.pdf</a></div><div class=""><br class=""></div><div class="">Cristel</div><div class=""><br class=""><div><blockquote type="cite" class=""><div class="">On Sep 1, 2016, at 7:14 PM, Wenqin SHAO <<a href="mailto:wenqin.shao@telecom-paristech.fr" class="">wenqin.shao@telecom-paristech.fr</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><meta http-equiv="Content-Type" content="text/html charset=us-ascii" class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">Dear list,<div class=""><br class=""></div><div class="">I encountered some cases where the actual time interval between two neighbouring measurements being much larger than the scheduled value.</div><div class="">Have you witnessed similar cases? I appreciate explanations on underlying reasons.</div><div class=""><br class=""></div><div class="">Here goes an example:</div><div class=""><span style="font-size: 11px; color: rgb(169, 183, 198); font-family: Menlo; background-color: rgb(43, 43, 43);" class=""><br class=""></span></div><div class=""><div class=""><font face="Menlo" class="">from ripe.atlas.cousteau import AtlasResultsRequest</font></div><div class=""><font face="Menlo" class="">filters = dict(msm_id=1010, probe_ids=[16981], start=1470055258, stop=1470056217)</font></div><div class=""><font face="Menlo" class="">is_success, results = AtlasResultsRequest(**filters).create()</font></div><div class=""><font face="Menlo" class="">if is_success:</font></div><div class=""><font face="Menlo" class=""> for mes in results:</font></div><div class=""><font face="Menlo" class=""> print mes.get('timestamp', -1)</font></div></div><div class=""><br class=""></div><div class=""><div class="">The above code requests some built-in ping measurements (240s interval) made by probe 16981 and prints their timestamps. See below for the execution result:</div></div><div class=""><br class=""></div><div style="margin: 0px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures;" class=""><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures;" class="">1470055259</span></div><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures" class="">1470055499</span></div><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures" class="">1470055978</span></div><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures;" class="">1470056216</span></div><div style="font-size: 11px;" class=""><br class=""></div></span></div><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures;" class="">Four measurements are retrieved within the given time range. I noticed that time interval between the 2nd and the 3rd measurement is 479s much larger than the planned value 240s.</span></div><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures;" class="">How come?</span></div><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures;" class=""><br class=""></span></div><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures;" class="">Many thanks for your attention.</span></div><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures;" class=""><br class=""></span></div><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures;" class="">Best regards,</span></div><div style="margin: 0px; line-height: normal;" class=""><span style="font-variant-ligatures: no-common-ligatures;" class="">wenqin</span></div></div></div></blockquote></div><br class=""></div></body></html>