[ovs-dev] [PATCH] ofproto: report coverage on hitting datapath flow limit

[Gowrishankar Muthukrishnan]

Hi,
Any more ack(s) required for this patch to be merged ?.

Regards,
Gowrishankar

On Thu, May 14, 2020 at 8:06 PM William Tu <u9012063 at gmail.com> wrote:

> On Mon, Apr 20, 2020 at 07:13:42PM +0530, Gowrishankar Muthukrishnan wrote:
> > Whenever the number of flows in the datapath crosses above
> > the flow limit set/autoconfigured, it is helpful to report
> > this event through coverage counter for an operator/devops
> > engineer to know and take proactive corrections in the
> > switch configuration.
> >
> > Today, these events are reported in ovs vswitch log when
> > a new flow can not be inserted in upcall processing in which
> > case ovs writes a warning, otherwise an auto correction
> > made by ovs to flush old flows without any intimation at all.
> >
> > Signed-off-by: Gowrishankar Muthukrishnan <gmuthukr at redhat.com>
> > ---
>
> Thanks, the patch looks good to me.
>
> I thought logging to ovs-vswitchd.log is good enough, because
> that's usually the first file we look, then if necessary we check
> the coverage log. Just curious, do you have some case where you
> keep seeing the flow_limit_hit frequently?
>
> Acked-by: William Tu <u9012063 at gmail.com>
>
> >  ofproto/ofproto-dpif-upcall.c | 6 ++++++
> >  1 file changed, 6 insertions(+)
> >
> > diff --git a/ofproto/ofproto-dpif-upcall.c
> b/ofproto/ofproto-dpif-upcall.c
> > index 5e08ef10d..a76532ec7 100644
> > --- a/ofproto/ofproto-dpif-upcall.c
> > +++ b/ofproto/ofproto-dpif-upcall.c
> > @@ -56,6 +56,7 @@ COVERAGE_DEFINE(handler_duplicate_upcall);
> >  COVERAGE_DEFINE(upcall_ukey_contention);
> >  COVERAGE_DEFINE(upcall_ukey_replace);
> >  COVERAGE_DEFINE(revalidate_missed_dp_flow);
> > +COVERAGE_DEFINE(upcall_flow_limit_hit);
> >
> >  /* A thread that reads upcalls from dpif, forwards each upcall's packet,
> >   * and possibly sets up a kernel flow as a cache. */
> > @@ -1281,6 +1282,7 @@ should_install_flow(struct udpif *udpif, struct
> upcall *upcall)
> >
> >      atomic_read_relaxed(&udpif->flow_limit, &flow_limit);
> >      if (udpif_get_n_flows(udpif) >= flow_limit) {
> > +        COVERAGE_INC(upcall_flow_limit_hit);
> >          VLOG_WARN_RL(&rl, "upcall: datapath flow limit reached");
> >          return false;
> >      }
> > @@ -2624,6 +2626,10 @@ revalidate(struct revalidator *revalidator)
> >           *       datapath flows, so we will recover before all the
> flows are
> >           *       gone.) */
> >          n_dp_flows = udpif_get_n_flows(udpif);
> > +        if (n_dp_flows >= flow_limit) {
> > +            COVERAGE_INC(upcall_flow_limit_hit);
> > +        }
> > +
> >          kill_them_all = n_dp_flows > flow_limit * 2;
> >          max_idle = n_dp_flows > flow_limit ? 100 : ofproto_max_idle;
> >
> > --
> > 2.21.1
> >
> > _______________________________________________
> > dev mailing list
> > dev at openvswitch.org
> > https://mail.openvswitch.org/mailman/listinfo/ovs-dev
>
>

-- 
Gowrishankar M