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From: Eric Dumazet <eric.dumazet@gmail.com>
To: sowmini varadhan <sowmini05@gmail.com>
Cc: Suprasad Mutalik Desai <suprasad.desai@gmail.com>,
	netdev <netdev@vger.kernel.org>,
	David Miller <davem@davemloft.ne>
Subject: Re: Fwd: Linux stack performance drop (TCP and UDP) in 3.10 kernel in routed scenario
Date: Wed, 04 Jun 2014 11:44:18 -0700	[thread overview]
Message-ID: <1401907458.3645.257.camel@edumazet-glaptop2.roam.corp.google.com> (raw)
In-Reply-To: <CACP96tQsfN9REHKZBJ7uWEr5kK04ScFPFMC8Zx7PMykoQg3yyg@mail.gmail.com>

On Wed, 2014-06-04 at 14:26 -0400, sowmini varadhan wrote:
> On Wed, Jun 4, 2014 at 10:59 AM, Eric Dumazet <eric.dumazet@gmail.com> wrote:
> 
> > Problem with IPv4 route cache is that is was too easy to flood it and
> > get worse performance.
> >
> > It had simply huge memory costs, and non predictable behavior [1]
> 
> Can you elaborate? Caches usually have an upper bound on
> the memory to be consumed by the cache, and from my reading
> of the 2.6.32 code, seems like it also had such limits (there was
> a sysctl tunable to turn off hashing, and rt_intern_hash() also had
> other bounds. Were these not enough?


http://vger.kernel.org/~davem/columbia2012.pdf


For gory details :

git log net/ipv4/route.c

  parent reply	other threads:[~2014-06-04 18:44 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <CAJMXqXZQ_S27LCZNJDjcQ9jy2qyJ0UT2nk+wdZOTQep+5rQZhQ@mail.gmail.com>
2014-06-04  9:04 ` Fwd: Linux stack performance drop (TCP and UDP) in 3.10 kernel in routed scenario Suprasad Mutalik Desai
2014-06-04 12:34   ` Eric Dumazet
2014-06-04 13:53     ` Suprasad Mutalik Desai
2014-06-04 14:59       ` Eric Dumazet
2014-06-04 16:34         ` Eric Dumazet
2014-06-04 18:03           ` Suprasad Mutalik Desai
2014-06-04 17:41         ` Suprasad Mutalik Desai
2014-06-04 18:26         ` sowmini varadhan
2014-06-04 18:32           ` Neal Cardwell
2014-06-04 18:44           ` Eric Dumazet [this message]
2014-06-04 19:18   ` David Miller
2014-06-05  2:17     ` Suprasad Mutalik Desai
2014-06-05  6:08       ` David Miller
2014-06-05  6:32       ` Eric Dumazet

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