On Wed 07-04-21 19:13:42, Bharata B Rao wrote: > On Wed, Apr 07, 2021 at 01:54:48PM +0200, Michal Hocko wrote: > > On Mon 05-04-21 11:18:48, Bharata B Rao wrote: > > > Hi, > > > > > > When running 10000 (more-or-less-empty-)containers on a bare-metal Power9 > > > server(160 CPUs, 2 NUMA nodes, 256G memory), it is seen that memory > > > consumption increases quite a lot (around 172G) when the containers are > > > running. Most of it comes from slab (149G) and within slab, the majority > > > of > > > it comes from kmalloc-32 cache (102G) > > > > Is this 10k cgroups a testing enviroment or does anybody really use that > > in production? I would be really curious to hear how that behaves when > > those containers are not idle. E.g. global memory reclaim iterating over > > 10k memcgs will likely be very visible. I do remember playing with > > similar setups few years back and the overhead was very high. > > This 10k containers is only a test scenario that we are looking at.
OK, this is good to know. I would definitely recommend looking at the runtime aspect of such a large scale deployment before optimizing for memory footprint. I do agree that the later is an interesting topic on its own but I do not expect such a deployment on small machines so the overhead shouldn't be a showstopper. I would be definitely interested to hear about the runtime overhead. I do expect some interesting finidings there. Btw. I do expect that memory controller will not be the only one deployed right? -- Michal Hocko SUSE Labs
