From mboxrd@z Thu Jan  1 00:00:00 1970
From: Qinglai Xiao <jigsaw-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Subject: =?utf-8?b?562U5aSNOiAgW1BBVENIXSBBZGQgdXNlciBkZWZpbmVk?=
 =?utf-8?q?_tag_calculation_callback_tolibrte=5Fdistributor=2E?=
Date: Thu, 6 Nov 2014 14:36:09 +0200
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To: Thomas Monjalon <thomas.monjalon-pdR9zngts4EAvxtiuMwx3w@public.gmane.org>,
 Bruce Richardson <bruce.richardson-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
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Hi Bruce,

There is a subtle case in which tag values are 2 and 3, respectively. Then =
these two tags cannot be distinguished. There should be a better way so as =
to handle this situation.

thx &
rgds
-qinglai

-----=E5=8E=9F=E5=A7=8B=E9=82=AE=E4=BB=B6-----
=E5=8F=91=E4=BB=B6=E4=BA=BA: "Thomas Monjalon" <thomas.monjalon-pdR9zngts4EAvxtiuMwx3w@public.gmane.org>
=E5=8F=91=E9=80=81=E6=97=B6=E9=97=B4: =E2=80=8E2014/=E2=80=8E11/=E2=80=8E6 =
12:36
=E6=94=B6=E4=BB=B6=E4=BA=BA: "Bruce Richardson" <bruce.richardson-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org=
>
=E6=8A=84=E9=80=81: "dev-VfR2kkLFssw@public.gmane.org" <dev-VfR2kkLFssw@public.gmane.org>; "jigsaw" <jigsaw@gmail.c=
om>
=E4=B8=BB=E9=A2=98: Re: [dpdk-dev] [PATCH] Add user defined tag calculation=
 callback tolibrte_distributor.

2014-11-06 09:22, Bruce Richardson:
> On Wed, Nov 05, 2014 at 07:24:13PM +0200, jigsaw wrote:
> > http://dpdk.org/browse/dpdk/tree/lib/librte_distributor/rte_distributor=
.c#n285
> >=20
> >         new_tag =3D (next_mb->hash.rss | 1);
> >=20
> > Why the logical OR is needed?
>=20
> That's needed to ensure that we never track a tag with an actual value of=
 zero.
> We instead always force the low bit to be 1, so that we can use zero as a=
n
> "empty" value.

Bruce, could you check how this code may be better commented please?
This discussion shows that the distributor library probably needs more
explanations in the code or doxygen.

Thanks
--=20
Thomas