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 -----????----- ???: "Thomas Monjalon" <thomas.monjalon at 6wind.com> ????: ?2014/?11/?6 12:36 ???: "Bruce Richardson" <bruce.richardson at intel.com> ??: "dev at dpdk.org" <dev at dpdk.org>; "jigsaw" <jigsaw at gmail.com> ??: 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 > > > > new_tag = (next_mb->hash.rss | 1); > > > > Why the logical OR is needed? > > 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 an > "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 -- Thomas
