Le 07/07/2016 18:16, Rick Jones a écrit : > On 07/07/2016 08:48 AM, Phil Sutter wrote: >> On Thu, Jul 07, 2016 at 02:59:48PM +0200, Nicolas Dichtel wrote: >>> Le 07/07/2016 13:17, Phil Sutter a écrit : >>> [snip] >>>> The issue came up during OpenStack Neutron testing, see this ticket for >>>> reference: >>>> >>>> https://bugzilla.redhat.com/show_bug.cgi?id=1310795 >>> Access to this ticket is not public :( >> >> *Sigh* OK, here are a few quotes: >> >> "OpenStack Neutron controller nodes, when undergoing testing, are >> locking up specifically during creation and mounting of namespaces. >> They appear to be blocking behind vfsmount_lock, and contention for the >> namespace_sem" >> >> "During the scale testing, we have 300 routers, 600 dhcp namespaces >> spread across four neutron network nodes. When then start as one set of >> standard Openstack Rally benchmark test cycle against neutron. An >> example scenario is creating 10x networks, list them, delete them and >> repeat 10x times. The second set performs an L3 benchmark test between >> two instances." >> > > Those 300 routers will each have at least one namespace along with the dhcp > namespaces. Depending on the nature of the routers (Distributed versus > Centralized Virtual Routers - DVR vs CVR) and whether the routers are supposed > to be "HA" there can be more than one namespace for a given router. > > 300 routers is far from the upper limit/goal. Back in HP Public Cloud, we > were > running as many as 700 routers per network node (*), and more than four > network > nodes. (back then it was just the one namespace per router and network). > Mileage > will of course vary based on the "oomph" of one's network node(s). Thank you for the details.
Do you have a script or something else to easily reproduce this problem?
