The qpid broker learns how many CPUs are available and will run more I/O threads when more CPUs are available (#CPUs + 1 threads). It would be interesting to see the results if your VM gets more CPUs.
-Steve > -----Original Message----- > From: CLIVE [mailto:[email protected]] > Sent: Wednesday, May 02, 2012 1:30 PM > To: James Kirkland > Cc: [email protected] > Subject: Re: QPID performance on virtual machines > > James, > > qpid-perf-test (as supplied with the qpid-0.14 source tar ball) runs a direct > queue test when executed without any parameters; there is a command line > option that enables this to be be changed if required. The message size is > 1024K (again default size when not explicitly set). And > 500000 messages are published by the test (again the default when not > explicitly set). All messages are transient so I wouldn't expect any file I/O > overhead to interfere with the test and this is confirmed by the vmstat > results I am seeing. The only jump in the vmstat output is the number of > context switches that are occurring which jumps up into the thousands. > > Clive > > On 02/05/2012 18:10, James Kirkland wrote: > > What sort of messging scenario is it? Are the messages persisted? > > How big are they? If they are persisted are you using virtual disks > > or physical devices? > > > > CLIVE wrote: > >> Hi all, > >> > >> I have been undertaking some performance profiling of QPID version > >> 0.14 over the last few weeks and I have found a significant > >> performance drop off when running QPID in a virtual machine. > >> > >> As an example if I run qpidd on an 8 core DELL R710 with 36G RAM > >> (RHEL5u5) and then run qpid-perf-test (on the same machine to > >> discount any network problems) without any command line parameters I > >> am seeing about 85,000 publish transfers/sec and 80000 consume > >> transfers/sec. If I run the same scenario on a VM (tried both KVM and > >> VMWare ESXi 4.3 running RHEL5u5) with 2 cores and 8G RAM, I am seeing > >> only 45000 publish transfers/sec and 40000 consume transfers/sec. A > >> significant drop off in performance. Looking at the cpu and memory > >> usage these would not seem to be the limiting factors as the memory > >> consumption of qpidd stays under 200 MBytes and its CPU is up at > >> about 150%; hence the two core machine. > >> > >> I have even run the same test on my Mac Book at home using VMWare > >> Fusion 4 ( 2 Core 4G RAM) and see the same 45000/40000 transfers/sec > >> results. > >> > >> I would expect a small drop off in performance when running in a VM, > >> but not to the extent that I am seeing. > >> > >> Has anyone else seen this and if so were they able to get to the > >> bottom of the issue. > >> > >> Any help would be appreciated. > >> > >> Clive Lilley > >> > > > > -- > > James Kirkland > > Principal Enterprise Solutions Architect > > 3340 Peachtree Road, NE, > > Suite 1200 > > Atlanta, GA 30326 USA. > > Phone (404) 254-6457 <https://www.google.com/voice#phones> > > RHCE Certificate: 805009616436562 --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
