04/07/2017 01:19, Dumitrescu, Cristian: > From: Thomas Monjalon [mailto:tho...@monjalon.net] > > 18/05/2017 11:09, Jianbo Liu: > > > Implement the same hash functions with crc32 on arm platform. > > > > > > Signed-off-by: Jianbo Liu <jianbo....@linaro.org> > > > --- > > > examples/ip_pipeline/pipeline/hash_func.h | 2 + > > > examples/ip_pipeline/pipeline/hash_func_arm64.h | 245 > > ++++++++++++++++++++++++ > > > 2 files changed, 247 insertions(+) > > > create mode 100644 examples/ip_pipeline/pipeline/hash_func_arm64.h > > > > I don't understand why this code is in an example. > > We have some CRC code in librte_hash, librte_net and ip_pipeline. > > Cristian, Jianbo, > > does it make sense to move these functions somewhere else? > > > > I think example apps are a great way to propose new hash functions. IMO we > should encourage the > definition/exploration of new hash functions in our example apps. > > These functions are examples of how fast hash functions can be built using > special CPU instructions. > They have much better performance than e.g. jhash, but their properties are > largely unknown, as no > rigorous study on their properties (such as uniform distribution) has been > conducted. I have seen them > providing good performance for the data set I have been using, but I have no > extensive data to support > their maturity level. > > If somebody is willing to invest the effort in proving them, I would be more > than happy to see them > moved to a library like librte_hash. Pablo as maintainer has the choice (I > think it is not the first time we > discuss bout these hash funcs :) ) > > As mentioned in one of our deprecation notices, I am actively working (not > ready for 17.8 unfortunately) > to add a key mask parameter to these functions, so more work on these hash > functions is likely to take place.
OK thanks for the explanation. I still think we do not need to prove hash for integrating them. I would be interested to read Pablo's opinion.
