[dpdk-dev] [PATCH v7 1/6] lib/eal: implement the family of PMD bit operation APIs

[Gavin Hu]

Hi Thomas,

> -----Original Message-----
> From: Thomas Monjalon <thomas at monjalon.net>
> Sent: Wednesday, April 1, 2020 5:45 PM
> To: Joyce Kong <Joyce.Kong at arm.com>; Gavin Hu <Gavin.Hu at arm.com>
> Cc: stephen at networkplumber.org; david.marchand at redhat.com;
> mb at smartsharesystems.com; jerinj at marvell.com;
> bruce.richardson at intel.com; ravi1.kumar at amd.com; rmody at marvell.com;
> shshaikh at marvell.com; xuanziyang2 at huawei.com;
> cloud.wangxiaoyun at huawei.com; zhouguoyang at huawei.com; Honnappa
> Nagarahalli <Honnappa.Nagarahalli at arm.com>; Phil Yang
> <Phil.Yang at arm.com>; nd <nd at arm.com>; dev at dpdk.org; nd
> <nd at arm.com>
> Subject: Re: [dpdk-dev] [PATCH v7 1/6] lib/eal: implement the family of PMD
> bit operation APIs
> 
> 01/04/2020 10:27, Gavin Hu:
> > Hi Thomas,
> >
> > From: Thomas Monjalon <thomas at monjalon.net>
> > >
> > > Hi,
> > >
> > > 09/03/2020 10:54, Joyce Kong:
> > > > Bitwise operation APIs are defined and used in a lot of PMDs,
> > > > which caused a huge code duplication.
> > >
> > > Statistics of the series: 653 insertions(+), 326 deletions(-)
> > > I would not say it is a huge duplication.
> > We did not include all PMDs, just a few for piloting and seeking opinions.
> > It is a huge duplication when counting all the PMDs.
> > >
> > > > To reduce duplication,
> > > > this patch consolidates them into a common API family.
> > > [...]
> > > > +PMD Bitops
> > > > +M: Joyce Kong <joyce.kong at arm.com>
> > > > +F: lib/librte_eal/common/include/rte_pmd_bitops.h
> > >
> > > Why is it called PMD bitops and not simply bitops?
> >
> > The scope of these APIs are decreased to PMD use only, for
> libraries/applications, it is recommended to use C11 directly as there are
> complications of more ordering models involved.
> 
> OK, but PMD means nothing, except this is where it is used *now*.
> Please describe and name the API with memory ordering words.
Will remove 'PMD' in v8.
The APIs were already named with a '_relaxed' suffix, for example 'rte_get_bit64_relaxed'. 
According to Honnappa, this patch set just address PMD's requirement, and the current PMDs are not using C11, so only '_relaxed' version is offered.
http://inbox.dpdk.org/dev/VE1PR08MB514983C3200859B27F166EBB983F0@VE1PR08MB5149.eurprd08.prod.outlook.com/