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
next prev 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 Regression: kernel 4.14 an later very slow with many ipsec tunnels 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
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