From: Thomas Monjalon <thomas@monjalon.net>
To: "Dumitrescu, Cristian" <cristian.dumitrescu@intel.com>,
pablo.de.lara.guarch@intel.com
Cc: dev@dpdk.org, Jianbo Liu <jianbo.liu@linaro.org>,
"jerin.jacob@caviumnetworks.com" <jerin.jacob@caviumnetworks.com>,
"ashwin.sekhar@caviumnetworks.com"
<ashwin.sekhar@caviumnetworks.com>
Subject: Re: [dpdk-dev] [PATCH] examples/ip_pipeline: use crc32 in hash functions for arm64
Date: Tue, 04 Jul 2017 01:25:59 +0200 [thread overview]
Message-ID: <1851401.bCM4vaXCYT@xps> (raw)
In-Reply-To: <3EB4FA525960D640B5BDFFD6A3D891267BA77E6C@IRSMSX108.ger.corp.intel.com>
04/07/2017 01:19, Dumitrescu, Cristian:
> From: Thomas Monjalon [mailto:thomas@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.liu@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.
next prev parent reply other threads:[~2017-07-03 23:26 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-05-18 9:09 Jianbo Liu
2017-07-03 21:11 ` Thomas Monjalon
2017-07-03 23:19 ` Dumitrescu, Cristian
2017-07-03 23:25 ` Thomas Monjalon [this message]
2017-07-04 13:55 ` De Lara Guarch, Pablo
2017-07-05 3:38 ` Jianbo Liu
2017-10-24 15:38 ` Dumitrescu, Cristian
2017-10-25 7:01 ` Jianbo Liu
2017-10-27 9:25 ` [dpdk-dev] [PATCH v2] " Jianbo Liu
2017-10-27 9:55 ` Dumitrescu, Cristian
2017-11-07 7:51 ` Ferruh Yigit
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