From: Eric Dumazet <dada1@cosmosbay.com>
To: Alexey Dobriyan <adobriyan@gmail.com>
Cc: David Miller <davem@davemloft.net>,
netdev@vger.kernel.org, shemminger@vyatta.com, "Zhang,
Yanmin" <yanmin_zhang@linux.intel.com>
Subject: Re: [PATCH] net: make sure struct dst_entry refcount is aligned on 64 bytes
Date: Fri, 14 Nov 2008 14:37:38 +0100 [thread overview]
Message-ID: <491D7F22.9020707@cosmosbay.com> (raw)
In-Reply-To: <20081114132230.GA27462@x200.localdomain>
Alexey Dobriyan a écrit :
> Hmm, indeed.
>
> I tried moving __refcnt et al to the very beginning, but it seems to make
> things worse (on x86_64, almost within statistical error).
>
> And there is no way to use offset_of() inside struct definition. :-(
Yes, it is important that the beginning of structure contain read mostly fields.
refcnt being the most written field (incremented / decremented for each packet),
it is really important to move it outside of the first 128 bytes
(192 bytes on 64 bit arches) of dst_entry
I wonder if some real hot dst_entries could be splitted (one copy for each stream),
to reduce ping-pongs.
next prev parent reply other threads:[~2008-11-14 13:37 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-11-14 8:09 [PATCH] net: speedup dst_release() Eric Dumazet
2008-11-14 8:54 ` David Miller
2008-11-14 9:04 ` Eric Dumazet
2008-11-14 9:36 ` Alexey Dobriyan
2008-11-14 10:47 ` [PATCH] net: make sure struct dst_entry refcount is aligned on 64 bytes Eric Dumazet
2008-11-14 11:35 ` Alexey Dobriyan
2008-11-14 11:43 ` Eric Dumazet
2008-11-14 13:22 ` Alexey Dobriyan
2008-11-14 13:37 ` Eric Dumazet [this message]
2008-11-17 3:46 ` David Miller
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