Re: [dpdk-dev] [PATCH v2 1/5] net/i40e: use relaxed and remove duplicate barrier

["Zhang, Qi Z" <qi.z.zhang@intel.com>]

> -----Original Message-----
> From: Gavin Hu (Arm Technology China) [mailto:Gavin.Hu@arm.com]
> Sent: Tuesday, September 17, 2019 11:24 AM
> To: Gavin Hu (Arm Technology China) <Gavin.Hu@arm.com>; Zhang, Qi Z
> <qi.z.zhang@intel.com>; dev@dpdk.org
> Cc: nd <nd@arm.com>; thomas@monjalon.net; Richardson, Bruce
> <bruce.richardson@intel.com>; Liu, Yong <yong.liu@intel.com>; Wang, Yinan
> <yinan.wang@intel.com>; ajit.khaparde@broadcom.com;
> somnath.kotur@broadcom.com; Honnappa Nagarahalli
> <Honnappa.Nagarahalli@arm.com>; Ruifeng Wang (Arm Technology China)
> <Ruifeng.Wang@arm.com>; Steve Capper <Steve.Capper@arm.com>
> Subject: RE: [dpdk-dev] [PATCH v2 1/5] net/i40e: use relaxed and remove
> duplicate barrier
> 
> Hi Qi,
> 
> > -----Original Message-----
> > From: dev <dev-bounces@dpdk.org> On Behalf Of Gavin Hu (Arm Technology
> > China)
> > Sent: Tuesday, September 17, 2019 10:08 AM
> > To: Zhang, Qi Z <qi.z.zhang@intel.com>; dev@dpdk.org
> > Cc: nd <nd@arm.com>; thomas@monjalon.net; Richardson, Bruce
> > <bruce.richardson@intel.com>; Liu, Yong <yong.liu@intel.com>; Wang,
> > Yinan <yinan.wang@intel.com>; ajit.khaparde@broadcom.com;
> > somnath.kotur@broadcom.com; Honnappa Nagarahalli
> > <Honnappa.Nagarahalli@arm.com>; Ruifeng Wang (Arm Technology China)
> > <Ruifeng.Wang@arm.com>; Steve Capper <Steve.Capper@arm.com>
> > Subject: Re: [dpdk-dev] [PATCH v2 1/5] net/i40e: use relaxed and
> > remove duplicate barrier
> >
> > Hi Qi,
> >
> > > -----Original Message-----
> > > From: Zhang, Qi Z <qi.z.zhang@intel.com>
> > > Sent: Tuesday, September 17, 2019 9:53 AM
> > > To: Gavin Hu (Arm Technology China) <Gavin.Hu@arm.com>;
> > dev@dpdk.org
> > > Cc: nd <nd@arm.com>; thomas@monjalon.net; Richardson, Bruce
> > > <bruce.richardson@intel.com>; Liu, Yong <yong.liu@intel.com>; Wang,
> > Yinan
> > > <yinan.wang@intel.com>; ajit.khaparde@broadcom.com;
> > > somnath.kotur@broadcom.com; Honnappa Nagarahalli
> > > <Honnappa.Nagarahalli@arm.com>; Ruifeng Wang (Arm Technology
> > China)
> > > <Ruifeng.Wang@arm.com>; Steve Capper <Steve.Capper@arm.com>
> > > Subject: RE: [dpdk-dev] [PATCH v2 1/5] net/i40e: use relaxed and
> > > remove duplicate barrier
> > >
> > >
> > >
> > > > -----Original Message-----
> > > > From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Gavin Hu
> > > > Sent: Monday, September 16, 2019 7:27 PM
> > > > To: dev@dpdk.org
> > > > Cc: nd@arm.com; thomas@monjalon.net; Richardson, Bruce
> > > > <bruce.richardson@intel.com>; Liu, Yong <yong.liu@intel.com>;
> > > > Wang,
> > > Yinan
> > > > <yinan.wang@intel.com>; ajit.khaparde@broadcom.com;
> > > > somnath.kotur@broadcom.com; Honnappa.Nagarahalli@arm.com;
> > > > ruifeng.wang@arm.com; steve.capper@arm.com
> > > > Subject: [dpdk-dev] [PATCH v2 1/5] net/i40e: use relaxed and
> > > > remove duplicate barrier
> > > >
> > > > To guarantee the orderings of successive stores to CIO and MMIO
> > memory,
> > > a
> > > > lighter weight rte_io_wmb [1] can be used instead of rte_wmb, and
> > since
> > > the
> > > > I40E_PCI_REG_WRITE API already has an inclusive rte_io_wmb, this
> > explicit
> > > call
> > > > can be even saved.
> > > >
> > > > [1]
> > http://git.dpdk.org/dpdk/tree/lib/librte_eal/common/include/generic/
> > > > rte_atomic.h#n98
> > > >
> > > > Signed-off-by: Gavin Hu <gavin.hu@arm.com>
> > >
> > > Can you also capture the one at the tail of i40e_xmit_pkts?
> > Thanks for your review, I will fix this in next version.
> I checked again, in this version, the rte_wmb at the tail of i40e_xmit_pkts was
> already removed and the following I40E_PCI_REG_WRITE_RELAXED was
> replaced by  I40E_PCI_REG_WRITE, which has an inclusive rte_io_wmb.

Sorry, I must mixed the with ice patch, yes you are right, its already there.

> > >
> > > Otherwise
> > > Acked-by: Qi Zhang <qi.z.zhang@intel.com>
> > >