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From: Thomas Graf <tgraf@suug.ch>
To: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: davem@davemloft.net, jeffrey.t.kirsher@intel.com,
	intel-wired-lan@lists.osuosl.org, netdev@vger.kernel.org,
	eric.dumazet@gmail.com
Subject: Re: [PATCH 0/3 net-next] Bring sizeof(net_device) down to < 2K bytes
Date: Fri, 10 Apr 2015 09:41:34 +0100	[thread overview]
Message-ID: <20150410084134.GA23070@casper.infradead.org> (raw)
In-Reply-To: <20150410000151.GA1728@Alexeis-MBP.westell.com>

On 04/09/15 at 05:01pm, Alexei Starovoitov wrote:
> On Fri, Apr 10, 2015 at 01:43:25AM +0200, Thomas Graf wrote:
> > The size of struct net_device crossed the 2K boundary a while ago which
> > is a waste in combination with many net namespaces. This series brings
> > the size of struct net_device down to well below 2K in total size with
> > a typical configuration. Some reserves a several holes leave room for
> > further expansion.
> 
> Great stuff!
> Can you share what was the sizeof(struct net_device) with typical
> x86 config before and after?

Before:

/* BRAIN FART ALERT! 2176 != 2091 + 41(holes), diff = 44 */

After:

/* size: 1984, cachelines: 31, members: 121 */
/* sum members: 1947, holes: 6, sum holes: 33 */
/* padding: 8 */
/* paddings: 2, sum paddings: 11 */

/* BRAIN FART ALERT! 1984 != 1947 + 33(holes), diff = 4 */

      reply	other threads:[~2015-04-10  8:41 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-04-09 23:43 [PATCH 0/3 net-next] Bring sizeof(net_device) down to < 2K bytes Thomas Graf
2015-04-09 23:43 ` [PATCH 1/3 net-next] e1000: Allocate pm_qos_req as needed Thomas Graf
2015-04-10  0:08   ` Jeff Kirsher
2015-04-10  4:35     ` [Intel-wired-lan] " Jeff Kirsher
2015-04-10  8:01       ` Daniel Borkmann
2015-04-10  8:48         ` Thomas Graf
2015-04-10  8:58           ` Jeff Kirsher
2015-04-09 23:43 ` [PATCH 2/3 net-next] net_device: Reorder members to fill holes Thomas Graf
2015-04-09 23:43 ` [PATCH 3/3 net-next] net_device: Add minimal padding to allow for net_device pointer alignment Thomas Graf
2015-04-10  0:34   ` Eric Dumazet
2015-04-10  8:48     ` Thomas Graf
2015-04-10  9:03       ` Eric Dumazet
2015-04-10  0:01 ` [PATCH 0/3 net-next] Bring sizeof(net_device) down to < 2K bytes Alexei Starovoitov
2015-04-10  8:41   ` Thomas Graf [this message]

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