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From: David Miller <davem@davemloft.net>
To: nickpiggin@yahoo.com.au
Cc: clameter@sgi.com, netdev@vger.kernel.org,
	herbert@gondor.apana.org.au, linux-kernel@vger.kernel.org
Subject: Re: 2.6.24-rc2: Network commit causes SLUB performance regression with tbench
Date: Tue, 13 Nov 2007 22:37:26 -0800 (PST)	[thread overview]
Message-ID: <20071113.223726.40898879.davem@davemloft.net> (raw)
In-Reply-To: <200711140514.28159.nickpiggin@yahoo.com.au>

From: Nick Piggin <nickpiggin@yahoo.com.au>
Date: Wed, 14 Nov 2007 05:14:27 +1100

> On Wednesday 14 November 2007 17:12, David Miller wrote:
> > Is your test system using HIGHMEM?
> >
> > That's one thing the page vector in the sk_buff can do a lot,
> > kmaps.
> 
> No, it's an x86-64, so no highmem.

Ok.

> What's also interesting is that SLAB apparently doesn't have this
> condition. The first thing that sprung to mind is that SLAB caches
> order > 0 allocations, while SLUB does not. However if anything,
> that should actually favour the SLUB numbers if network is avoiding
> order > 0 allocations.
> 
> I'm doing some oprofile runs now to see if I can get any more info.

Here are some other things you can play around with:

1) Monitor the values of skb->len and skb->data_len for packets
   going over loopback.

2) Try removing NETIF_F_SG in drivers/net/loopback.c's dev->feastures
   setting.

  reply	other threads:[~2007-11-14  6:37 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-11-09 12:36 2.6.24-rc2 slab vs slob tbench numbers Nick Piggin
2007-11-09 15:15 ` Christoph Lameter
2007-11-09 17:49   ` Christoph Lameter
2007-11-09 23:46     ` 2.6.24-rc2: Network commit causes SLUB performance regression with tbench Christoph Lameter
2007-11-10  1:29       ` Nick Piggin
2007-11-10  3:28         ` Nick Piggin
2007-11-12 19:44         ` Christoph Lameter
2007-11-13 11:41           ` Nick Piggin
2007-11-14  1:58             ` David Miller
2007-11-13 17:36               ` Nick Piggin
2007-11-14  6:12                 ` David Miller
2007-11-13 18:14                   ` Nick Piggin
2007-11-14  6:37                     ` David Miller [this message]
2007-11-13 22:27                       ` Nick Piggin
2007-11-13 22:55                         ` Nick Piggin
2007-11-14 11:10                         ` David Miller
2007-11-13 23:39                           ` Nick Piggin
2007-11-14 11:48                           ` Herbert Xu
2007-11-14  0:02                             ` Nick Piggin
2007-11-14 12:10                               ` David Miller
2007-11-14 18:33                                 ` Christoph Lameter
2007-11-14 23:46                             ` David Miller
2007-11-15  0:21                               ` Nick Piggin
2007-11-15  0:27                                 ` David Miller
2007-11-15  1:03                               ` Christoph Lameter
2007-11-15  1:11                                 ` Herbert Xu
2007-11-15  1:47                                   ` Nick Piggin
2007-11-12 20:13 ` 2.6.24-rc2 slab vs slob tbench numbers Matt Mackall
2007-11-13 11:44   ` Nick Piggin

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