<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><br><div><div>On Mar 2, 2012, at 12:50 PM, Jay Pipes wrote:</div><blockquote type="cite"><div><font class="Apple-style-span" color="#000000"><br></font>We are not using multiprocessing, no.<br><br>We simply start multiple worker processes listening on the same socket, with each worker process having an eventlet greenthread pool.<br><br>You can see the code (taken from Swift and adapted by Chris Behrens and Brian Waldon to use the object-oriented Server approach that Glance/Keystone/Nova uses) here:<br><br><a href="https://github.com/openstack/glance/blob/master/glance/common/wsgi.py">https://github.com/openstack/glance/blob/master/glance/common/wsgi.py</a><br><br>There is a worker = XXX configuration option that controls the number of worker processes created on server startup. A worker value of 0 indicates to run identically to the way Nova currently runs (one process with an eventlet pool of greenthreads)</div></blockquote><br></div><div>This would be excellent to add to nova as an option for performance reasons. Especially since you can fallback to the 0 version. I'm always concerned with mixing threading and eventlet as it leads to really odd bugs, but it sounds like HP has vetted it. If we keep 0 as the default I don't see any reason why it couldn't be added.</div><div><br></div><div>Vish</div></body></html>