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From: Eric Dumazet <eric.dumazet@gmail.com>
To: David Miller <davem@davemloft.net>
Cc: netdev <netdev@vger.kernel.org>
Subject: Re: [PATCH net-next] fib_hash: embed initial hash table in fn_zone
Date: Thu, 14 Oct 2010 21:22:39 +0200	[thread overview]
Message-ID: <1287084159.2659.0.camel@edumazet-laptop> (raw)
In-Reply-To: <1287073458.2712.100.camel@edumazet-laptop>

Le jeudi 14 octobre 2010 à 18:24 +0200, Eric Dumazet a écrit :
> While looking for false sharing problems, I noticed 
> sizeof(struct fn_zone) was small (28 bytes) and possibly sharing a cache
> line with an often written kernel structure.
> 
> Most of the time, fn_zone uses its initial hash table of 16 slots.
> 
> We can avoid the false sharing problem by embedding this initial hash
> table in fn_zone itself, so that sizeof(fn_zone) > L1_CACHE_BYTES
> 
> We did a similar optimization in commit a6501e080c (Reduce memory needs
> and speedup lookups)
> 
> Add a fz_revorder field to speedup fn_hash() a bit.
> 
> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>

Oops, a last minute change was wrong, I'll resend a V2.

Thanks



  reply	other threads:[~2010-10-14 19:29 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-10-14 16:24 [PATCH net-next] fib_hash: embed initial hash table in fn_zone Eric Dumazet
2010-10-14 19:22 ` Eric Dumazet [this message]
2010-10-15  6:53   ` [PATCH net-next 1/3] " Eric Dumazet

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