netdev - [RFC 2/2] udp: udp_lib_get_port start at a different bucket on different processors

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Date:	Wed, 16 Dec 2009 21:24:44 +0200
From:	Lucian Adrian Grijincu <lgrijincu@...acom.com>
To:	netdev@...r.kernel.org
CC:	Octavian Purdila <opurdila@...acom.com>
Subject: [RFC 2/2] udp: udp_lib_get_port start at a different bucket on different
 processors

On SMP, when ports are not allocated randomly, using the same starting
port on all processors will lead to bad performance as all processors
will try to get the same hashbucket spinlock: only one will succeed,
the rest will spin madly.

We solve this problem by making each processor start searching from a
different port. To not skip possibly valid port ranges we renormalize
the hint value too.

Signed-off-by: Lucian Adrian Grijincu <lgrijincu@...acom.com>
---
  net/ipv4/udp.c |   12 +++++++++---
  1 files changed, 9 insertions(+), 3 deletions(-)

View attachment "0002-udp-udp_lib_get_port-start-at-a-different-bucket-on-.patch" of type "text/x-patch" (985 bytes)