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From: Eric Dumazet <dada1@cosmosbay.com>
To: Eric Dumazet <dada1@cosmosbay.com>
Cc: Pavel Emelyanov <xemul@openvz.org>,
	Linux Netdev List <netdev@vger.kernel.org>,
	Stephen Hemminger <shemminger@vyatta.com>,
	Patrick McHardy <kaber@trash.net>
Subject: Re: [PATCH net-2.6.26 1/2] Shrink size of net_device by filling alignment holes in it.
Date: Mon, 07 Apr 2008 19:17:11 +0200	[thread overview]
Message-ID: <47FA5717.4070901@cosmosbay.com> (raw)
In-Reply-To: <47FA5426.10704@cosmosbay.com>

Eric Dumazet a écrit :
> Pavel Emelyanov a écrit :
>> I've found a much easier way to shrink the net_device structure 
>> rather that moving all the operations out of it. However, since
>> the net_device may grow further, moving the operations into a
>> separate place may look reasonable.
>>
>> The pahole tool showed, that there are a 124 and 80 bytes holes
>> before the queue_lock and the _xmit_lock respectively. Moving most
>> of the devices callbacks into the 2nd hole makes the sizeof of the
>> structure be 1024 bytes.
>>
>>   
> On 32 bits platform and CONFIG_X86_L1_CACHE_SHIFT=7
> I presume :)
>
> Could you check if x86_64 machines with  X86_L1_CACHE_SHIFT = 7 or 8 
> dont suffer from this patch ?
>
> At first glance I would say it seems OK, but this net_device is really 
> touchy for SMP performance :)
I meant :

X86_L1_CACHE_SHIFT = 6 (MK8 | MCORE2)  or 7 (others)






  reply	other threads:[~2008-04-07 17:17 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-04-07 16:25 [PATCH net-2.6.26 1/2] Shrink size of net_device by filling alignment holes in it Pavel Emelyanov
2008-04-07 17:04 ` Eric Dumazet
2008-04-07 17:17   ` Eric Dumazet [this message]
2008-04-07 17:47     ` Arnaldo Carvalho de Melo
2008-04-08  8:41       ` Pavel Emelyanov
2008-04-16  9:12         ` David Miller

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