So I *think* this is an issue because of the extremely large number of consumers. The threading model in v6 means that whenever a network read occurs for a connection, it iterates over the consumers on that connection - obviously where there are a large number of consumers this is burdensome. I fear addressing this may not be a trivial change... I shall spend the rest of my afternoon pondering this...
- Rob On 15 October 2016 at 17:14, Ramayan Tiwari <ramayan.tiw...@gmail.com> wrote: > Hi Rob, > > Thanks so much for your response. We use transacted sessions with > non-persistent delivery. Prefetch size is 1 and every message is same size > (200 bytes). > > Thanks > Ramayan > > On Sat, Oct 15, 2016 at 2:59 AM, Rob Godfrey <rob.j.godf...@gmail.com> > wrote: > > > Hi Ramyan, > > > > this is interesting... in our testing (which admittedly didn't cover the > > case of this many queues / listeners) we saw the 6.0.x broker using less > > CPU on average than the 0.32 broker. I'll have a look this weekend as to > > why creating the listeners is slower. On the dequeing, can you give a > > little more information on the usage pattern - are you using > transactions, > > auto-ack or client ack? What prefetch size are you using? How large are > > your messages? > > > > Thanks, > > Rob > > > > On 14 October 2016 at 23:46, Ramayan Tiwari <ramayan.tiw...@gmail.com> > > wrote: > > > > > Hi All, > > > > > > We have been validating the new Qpid broker (version 6.0.4) and have > > > compared against broker version 0.32 and are seeing major regressions. > > > Following is the summary of our test setup and results: > > > > > > *1. Test Setup * > > > *a). *Qpid broker runs on a dedicated host (12 cores, 32 GB RAM). > > > *b).* For 0.32, we allocated 16 GB heap. For 6.0.6 broker, we use 8GB > > > heap and 8GB direct memory. > > > *c).* For 6.0.4, flow to disk has been configured at 60%. > > > *d).* Both the brokers use BDB host type. > > > *e).* Brokers have around 6000 queues and we create 16 listener > > > sessions/threads spread over 3 connections, where each session is > > listening > > > to 3000 queues. However, messages are only enqueued and processed from > 10 > > > queues. > > > *f).* We enqueue 1 million messages across 10 different queues > (evenly > > > divided), at the start of the test. Dequeue only starts once all the > > > messages have been enqueued. We run the test for 2 hours and process as > > > many messages as we can. Each message runs for around 200 milliseconds. > > > *g).* We have used both 0.16 and 6.0.4 clients for these tests (6.0.4 > > > client only with 6.0.4 broker) > > > > > > *2. Test Results * > > > *a).* System Load Average (read notes below on how we compute it), > for > > > 6.0.4 broker is 5x compared to 0.32 broker. During start of the test > > (when > > > we are not doing any dequeue), load average is normal (0.05 for 0.32 > > broker > > > and 0.1 for new broker), however, while we are dequeuing messages, the > > load > > > average is very high (around 0.5 consistently). > > > > > > *b). *Time to create listeners in new broker has gone up by 220% > > compared > > > to 0.32 broker (when using 0.16 client). For old broker, creating 16 > > > sessions each listening to 3000 queues takes 142 seconds and in new > > broker > > > it took 456 seconds. If we use 6.0.4 client, it took even longer at > 524% > > > increase (887 seconds). > > > *I).* The time to create consumers increases as we create more > > > listeners on the same connections. We have 20 sessions (but end up > using > > > around 5 of them) on each connection and we create about 3000 consumers > > and > > > attach MessageListener to it. Each successive session takes longer > > > (approximately linear increase) to setup same number of consumers and > > > listeners. > > > > > > *3). How we compute System Load Average * > > > We query the Mbean SysetmLoadAverage and divide it by the value of > MBean > > > AvailableProcessors. Both of these MBeans are available under > > > java.lang.OperatingSystem. > > > > > > I am not sure what is causing these regressions and would like your > help > > in > > > understanding it. We are aware about the changes with respect to > > threading > > > model in the new broker, are there any design docs that we can refer to > > > understand these changes at a high level? Can we tune some parameters > to > > > address these issues? > > > > > > Thanks > > > Ramayan > > > > > >
