[ovs-discuss] warning messages regarding buffer space and unknown buffer

[junaid khalid]

Thanks a lot. I will update you after testing it

On Wed, Apr 25, 2012 at 10:45 AM, Ben Pfaff <blp at nicira.com> wrote:

> On Wed, Apr 25, 2012 at 10:38:45AM +0500, junaid khalid wrote:
> > we are talking about the recv failed problem (system at br0: recv failed
> (No
> > buffer space available)).
>
> Try applying the following patch from master to your tree.  It may help.
>
> --8<--------------------------cut here-------------------------->8--
>
> From: Ben Pfaff <blp at nicira.com>
> Date: Thu, 15 Mar 2012 21:15:38 -0700
> Subject: [PATCH] netlink-socket: Increase Netlink socket receive buffer
> size.
>
> Open vSwitch userspace can set up flows at a high rate, but it is somewhat
> "bursty" in opportunities to set up flows, by which I mean that OVS sets up
> a batch of flows, then goes off and does some other work for a while, then
> sets up another batch of flows, and so on.  The result is that, if a large
> number of packets that need flow setups come in all at once, then some of
> them can overflow the relatively small kernel-to-user buffers.
>
> This commit increases the kernel-to-user buffers from the default of
> approximately 120 kB each to 1 MB each.  In one somewhat synthetic test
> case that I ran based on an "hping3" that generated a load of about 20,000
> new flows per second (including both requests and replies), this reduced
> the packets dropped at the kernel-to-user interface from about 30% to none.
> I expect that it will similarly improve packet loss in workloads where
> flow arrival is not easily predictable.
>
> (This has little effect on workloads generated by "ovs-benchmark rate"
> because that benchmark is effectively "self-clocking", that is, a new flow
> is triggered only by a reply to a request made earlier, which means that
> the number of buffered packets at any given has a known, constant upper
> limit.)
>
> Bug #10210.
> Signed-off-by: Ben Pfaff <blp at nicira.com>
> ---
>  include/sparse/sys/socket.h |    5 +++--
>  lib/netlink-socket.c        |   10 +++++++++-
>  2 files changed, 12 insertions(+), 3 deletions(-)
>
> diff --git a/include/sparse/sys/socket.h b/include/sparse/sys/socket.h
> index 89e3c2d..1ed195b 100644
> --- a/include/sparse/sys/socket.h
> +++ b/include/sparse/sys/socket.h
> @@ -1,5 +1,5 @@
>  /*
> - * Copyright (c) 2011 Nicira Networks.
> + * Copyright (c) 2011, 2012 Nicira Networks.
>  *
>  * Licensed under the Apache License, Version 2.0 (the "License");
>  * you may not use this file except in compliance with the License.
> @@ -74,7 +74,8 @@ enum {
>     SO_SNDBUF,
>     SO_SNDLOWAT,
>     SO_SNDTIMEO,
> -    SO_TYPE
> +    SO_TYPE,
> +    SO_RCVBUFFORCE
>  };
>
>  enum {
> diff --git a/lib/netlink-socket.c b/lib/netlink-socket.c
> index bc46235..df6f1d8 100644
> --- a/lib/netlink-socket.c
> +++ b/lib/netlink-socket.c
> @@ -1,5 +1,5 @@
>  /*
> - * Copyright (c) 2008, 2009, 2010, 2011 Nicira Networks.
> + * Copyright (c) 2008, 2009, 2010, 2011, 2012 Nicira Networks.
>  *
>  * Licensed under the Apache License, Version 2.0 (the "License");
>  * you may not use this file except in compliance with the License.
> @@ -89,6 +89,7 @@ nl_sock_create(int protocol, struct nl_sock **sockp)
>     struct nl_sock *sock;
>     struct sockaddr_nl local, remote;
>     socklen_t local_size;
> +    int rcvbuf;
>     int retval = 0;
>
>     if (!max_iovs) {
> @@ -122,6 +123,13 @@ nl_sock_create(int protocol, struct nl_sock **sockp)
>     sock->protocol = protocol;
>     sock->dump = NULL;
>
> +    rcvbuf = 1024 * 1024;
> +    if (setsockopt(sock->fd, SOL_SOCKET, SO_RCVBUFFORCE,
> +                   &rcvbuf, sizeof rcvbuf)) {
> +        VLOG_WARN_RL(&rl, "setting %d-byte socket receive buffer failed
> (%s)",
> +                     rcvbuf, strerror(errno));
> +    }
> +
>     retval = get_socket_rcvbuf(sock->fd);
>     if (retval < 0) {
>         retval = -retval;
> --
> 1.7.2.5
>
>
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