linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Steffen Klassert <steffen.klassert@secunet.com>
To: Florian Westphal <fw@strlen.de>
Cc: David Miller <davem@davemloft.net>, <linux@stwm.de>,
	<netdev@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
	<torvalds@linux-foundation.org>, <christophe.gouault@6wind.com>
Subject: Re: Regression: kernel 4.14 an later very slow with many ipsec tunnels
Date: Fri, 14 Sep 2018 07:06:51 +0200	[thread overview]
Message-ID: <20180914050651.GD23674@gauss3.secunet.de> (raw)
In-Reply-To: <20180913210325.5usfj2rorvuvtyc7@breakpoint.cc>

On Thu, Sep 13, 2018 at 11:03:25PM +0200, Florian Westphal wrote:
> David Miller <davem@davemloft.net> wrote:
> > From: Florian Westphal <fw@strlen.de>
> > Date: Thu, 13 Sep 2018 18:38:48 +0200
> > 
> > > Wolfgang Walter <linux@stwm.de> wrote:
> > >> What I can say is that it depends mainly on number of policy rules and SA.
> > > 
> > > Thats already a good hint, I guess we're hitting long hash chains in
> > > xfrm_policy_lookup_bytype().
> > 
> > I don't really see how recent changes can influence that.
> 
> I don't think there is a recent change that did this.
> 
> Walter says < 4.14 is ok, so this is likely related to flow cache removal.
> 
> F.e. it looks like all prefixed policies end up in a linked list
> (net->xfrm.policy_inexact) and are not even in a hash table.
> 
> I am staring at b58555f1767c9f4e330fcf168e4e753d2d9196e0
> but can't figure out how to configure that away from the
> 'no hashing for prefixed policies' default or why we even have
> policy_inexact in first place :/

The hash threshold can be configured like this:

ip x p set hthresh4 0 0

This sets the hash threshold to local /0 and remote /0 netmasks.
With this configuration, all policies should go to the hashtable.
This might help to balance the hash chains better.

Default hash thresholds are local /32 and remote /32 netmasks, so
all prefixed policies go to the inexact list.

To view the configuration:

ip -s -s x p count


  parent reply	other threads:[~2018-09-14  5:06 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-09-13 11:30 Wolfgang Walter
2018-09-13 13:58 ` Florian Westphal
2018-09-13 15:46   ` Wolfgang Walter
2018-09-13 16:38     ` Florian Westphal
2018-09-13 17:23       ` David Miller
2018-09-13 21:03         ` Florian Westphal
2018-09-13 21:12           ` David Miller
2018-09-14  5:06           ` Steffen Klassert [this message]
2018-09-14  5:54             ` Florian Westphal
2018-09-14  6:01               ` Steffen Klassert
2018-09-14  8:01                 ` Christophe Gouault
2018-09-14 11:49               ` Wolfgang Walter
2018-10-02 14:45               ` Wolfgang Walter
2018-10-02 14:56                 ` Florian Westphal
2018-10-02 17:34                   ` Wolfgang Walter
2018-10-02 21:35                     ` Florian Westphal
2018-10-04 13:57                       ` Wolfgang Walter
2018-10-25  9:38                         ` Wolfgang Walter
2018-10-25 17:34                           ` David Miller
2018-10-25 19:24                             ` Florian Westphal
2018-10-26 12:18                             ` Wolfgang Walter
2018-10-25 22:45                           ` Florian Westphal

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20180914050651.GD23674@gauss3.secunet.de \
    --to=steffen.klassert@secunet.com \
    --cc=christophe.gouault@6wind.com \
    --cc=davem@davemloft.net \
    --cc=fw@strlen.de \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux@stwm.de \
    --cc=netdev@vger.kernel.org \
    --cc=torvalds@linux-foundation.org \
    --subject='Re: Regression: kernel 4.14 an later very slow with many ipsec tunnels' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).