[lvs-users] 100% CPU usage in si

Julian Anastasov ja at ssi.bg
Tue Feb 25 08:12:43 GMT 2014


On Mon, 24 Feb 2014, Vincent Bernat wrote:

> Hi!
> With Linux 3.2, no sync daemon, only using DR, conntrack disabled, about
> 100k connections in IPVS, we get 100% CPU usage, all in soft
> interrupts. A few seconds before, CPU usage was very low. We are able to
> get back to normal by reducing the traffic going through the box. Once
> the problem is resoved, CPU usage becomes low again. So, it seems that
> we hit some "ceiling".
> Are there known problems with IPVS and Linux 3.2?

	Not of that sort. We expect load to increase
linearly until some point, not with jumps. This is
for normal setup. If testing with client on LAN from
small number of machines it is possible test to be
influenced from limit in client ports or other kind
of problems. It is possible with 'perf top' to
catch if some place popups in stats on high load.

	Note that 3.10 comes with some optimizations
to reduce routing/dst refcnt usage and also switching
to RCU. There should be some gain from this, if using


Julian Anastasov <ja at ssi.bg>

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