> -----Original Message----- > From: dev [mailto:dev-boun...@dpdk.org] On Behalf Of Pragash > Vijayaragavan > Sent: Wednesday, August 23, 2017 3:16 PM > To: dev@dpdk.org > Cc: Minseok Kwon <mxk...@rit.edu> > Subject: [dpdk-dev] cuckoo hash in dpdk > > Hi, > > I got the chance to look at the cuckoo hash used in dpdk and have a query. > > would using division and modulo operations be slower than bitwise > operations on RTE_HASH_BUCKET_ENTRIES, specially since > RTE_HASH_BUCKET_ENTRIES is a power of 2. > For example, to do a modulo we can do a "AND" operation on > (RTE_HASH_BUCKET_ENTRIES - 1), which might be faster. We did a cuckoo > filter for VPP and doing this gave a slight improvement in speed. > Is there any particular reason its done this way. > > Sorry if i am being wrong in any way, i was just curious. > > Thanks, > > Pragash Vijayaragavan > Grad Student at Rochester Institute of Technology > email : pxv3...@rit.edu > ph : 585 764 4662
Bitwise AND typically takes 1 cycle on any CPU, while modulo takes dozens of cycles.
