<div dir="ltr"><div dir="ltr">I attempted to reproduce the original breakdown around 3000 CPS using the default 212992 byte receive buffer and could not, which tells me I broke a cardinal rule of load testing and changed more than one thing at a time. Also, don't do load testing when tired. I suspect that I had also made a change to the sipp scenario recv/sched loops, or I had unknowingly broken something while checking out the tuned package.<br clear="all"><div><div dir="ltr" class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><br></div><div>I deeply appreciate Alex's instance that I was wrong and to keep digging. I am happy to retract my claim regarding "absolutely terrible sysctl defaults". Using synchronous/blocking DB queries, the 8-core server reached 14,000 CPS, at which point I declared it fixed and went to bed. It could probably go higher: there's only one DB query with a <10ms response time, Memcache for the query response, and some logic to decide how to respond. There's only a single non-200 final response, so it's probably as minimalist as it gets.</div><div><br></div><div>If anyone else is trying to tune their setup, I think Alex's advice to "not run more than 2 * (CPU threads) [children]" is the best place to start. I had inherited this project from someone else's work under version 1.11 and they had used 128 children. They were using remote DB servers with much higher latency than the local DBs we have today, so that might have been the reason. Or they were just wrong to being with.</div><div><br></div><div>The Description for Asynchronous Statements is extremely tempting and was what started me down that path; it might be missing a qualification that
Async can be an improvement for slow blocking operations, but the additional overhead may be a disadvantage for very fast blocking operations. </div><div><br></div><div>Thank you to everyone who responded to this topic. </div><div dir="ltr"><br></div><div dir="ltr">Regards,<div><br></div><div><p style="font-family:helvetica,arial,sans-serif;font-size:12px;margin:0px;padding:0px 0px 20px;color:rgb(0,0,0)"><strong>Calvin Ellison</strong><br>Senior Voice Operations Engineer<br><a href="mailto:calvin.ellison@voxox.com" style="text-decoration:none;color:rgb(14,123,174)" target="_blank">calvin.ellison@voxox.com</a><br></p></div></div></div></div></div></div></div></div><br></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Fri, Jun 12, 2020 at 6:42 PM Alex Balashov <<a href="mailto:abalashov@evaristesys.com">abalashov@evaristesys.com</a>> wrote:</div></div></div>