[ovs-dev] [PATCH 6/9] More compact ofpact_set_field.

Ben Pfaff blp at nicira.com
Thu Oct 17 22:22:51 UTC 2013


On Thu, Oct 17, 2013 at 03:12:02PM -0700, Jarno Rajahalme wrote:
> 
> On Oct 17, 2013, at 12:40 PM, Ben Pfaff <blp at nicira.com> wrote:
> 
> > On Wed, Oct 16, 2013 at 04:16:08PM -0700, Jarno Rajahalme wrote:
> >> Signed-off-by: Jarno Rajahalme <jrajahalme at nicira.com>
> > 
> > Why is saving space here worthwhile?
> 
> The difference in setting an IPv4 address, any register, port number,
> etc., is 8 bytes vs. 24 bytes (i.e, factor of three). I thought this
> could be significant for cases where there are a lot of actions. There
> is one constructor for them, and rest of the code usually does not
> need to care about it, other than using an accessor to get the data
> pointer. Otherwise on the source level the data members can be
> accessed quite much like with the union mf_value, so I thought it
> turned out quite nice :-)
> 
> However, I explicitly put this in as a separate patch so that you can
> say what you think.

I appreciate the thought, and I'm sure that the implementation is fine,
but I don't think saving memory here is important enough.



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