[ovs-discuss] ovs-ofctl fails occasionally

[Ken Ajiro]

  Ben,

> The following stopgap appears to fix the problem on master.  I suspect
> it could be easily backported as far as necessary.  Does it work for you
> too?

  Yes, it worked.  Thank you for your support.

  Thanks,
  Ken

 On Thu, 28 Feb 2019 00:12:54 +0000,
 blp at ovn.org wrote
 in E-mail "Re: [ovs-discuss] ovs-ofctl fails occasionally":

> On Wed, Feb 27, 2019 at 12:45:58PM +0000, Ken Ajiro wrote:
> > 
> >   Hello,
> > 
> >   When I use ovs-ofctl on OVS 2.10.1, it failed occasionally by error:
> > 
> >     ovs-ofctl: br0: failed to connect to socket (Broken pipe)
> > 
> >   This error is possible to be reproduced with:
> > 
> >     # while :; do /opt/nec/pf/ds/bin/ovs-ofctl --timeout=5 dump-flows br0 > /tmp/log || break; done; cat /tmp/log
> >     ovs-ofctl: br0: failed to connect to socket (Broken pipe)
> > 
> >   Also I tried with OVS 2.4.1 and could not reproduce this error.
> > 
> >   I think that recently rconn.c was modified on commit 476d2551abd2871696a64203f78d658ac2d7f32c
> >   and the connection for ofctl was changed it begins on state S_CONNECTING instead of S_ACTIVE.
> >   So timeout_CONNECTING will be applied for ofctl connection, however timeout_CONNECTING is 1
> >   and this is too short (e.g. if transition time of CONNCTING was 12:00:00.999, it will be timed out
> >   after 1ms). I think that this is cause of occasionally disconnection of ofctl.
> 
> Thanks for the report.
> 
> It seems to me that the right long-term fix is to use higher resolution
> (e.g. millisecond resolution) to measure the timeouts.  However, that
> will be a relatively large fix.
> 
> The following stopgap appears to fix the problem on master.  I suspect
> it could be easily backported as far as necessary.  Does it work for you
> too?
> 
> diff --git a/lib/rconn.c b/lib/rconn.c
> index 48ae8c6a72e5..8ca23cbcfe90 100644
> --- a/lib/rconn.c
> +++ b/lib/rconn.c
> @@ -502,7 +502,7 @@ static unsigned int
>  timeout_CONNECTING(const struct rconn *rc)
>      OVS_REQUIRES(rc->mutex)
>  {
> -    return MAX(1, rc->backoff);
> +    return MAX(2, rc->backoff);
>  }
>  
>  static void