From: David Ahern <dsahern@gmail.com>
To: Heiner Kallweit <hkallweit1@gmail.com>,
David Miller <davem@davemloft.net>
Cc: "netdev@vger.kernel.org" <netdev@vger.kernel.org>,
David Laight <David.Laight@ACULAB.COM>
Subject: Re: [PATCH net-next v2] net: core: change bool members of struct net_device to bitfield members
Date: Tue, 9 Oct 2018 14:43:27 -0600 [thread overview]
Message-ID: <f8bbbd11-0ad2-77e6-c4fe-e3f643e7e243@gmail.com> (raw)
In-Reply-To: <ded0a778-ca20-4e0f-223d-da3eb5cd71b2@gmail.com>
On 10/9/18 2:24 PM, Heiner Kallweit wrote:
> Reordering the struct members to fill the holes could be a little tricky
> and could have side effects because it may make a performance difference
> whether certain members are in one cacheline or not.
> And whether it's worth to spend this effort (incl. the related risks)
> just to save a few bytes (also considering that typically we have quite
> few instances of struct net_device)?
>
It would be good to get net_device below 2048 without affecting
performance. Anything else is just moving elements around for the same
end allocation (rounds up to 4096).
next prev parent reply other threads:[~2018-10-10 4:02 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-08 20:17 [PATCH net-next v2] net: core: change bool members of struct net_device to bitfield members Heiner Kallweit
2018-10-09 15:20 ` David Ahern
2018-10-09 20:24 ` Heiner Kallweit
2018-10-09 20:43 ` David Ahern [this message]
2018-10-09 20:52 ` Eric Dumazet
2018-10-10 8:59 ` David Laight
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