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

[Gavin Hu (Arm Technology China)]

Hi Qi, 

> -----Original Message-----
> From: dev <dev-boun...@dpdk.org> On Behalf Of Gavin Hu (Arm
> Technology China)
> Sent: Tuesday, September 17, 2019 10:08 AM
> To: Zhang, Qi Z <qi.z.zh...@intel.com>; dev@dpdk.org
> Cc: nd <n...@arm.com>; tho...@monjalon.net; Richardson, Bruce
> <bruce.richard...@intel.com>; Liu, Yong <yong....@intel.com>; Wang,
> Yinan <yinan.w...@intel.com>; ajit.khapa...@broadcom.com;
> somnath.ko...@broadcom.com; Honnappa Nagarahalli
> <honnappa.nagaraha...@arm.com>; Ruifeng Wang (Arm Technology China)
> <ruifeng.w...@arm.com>; Steve Capper <steve.cap...@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.zh...@intel.com>
> > Sent: Tuesday, September 17, 2019 9:53 AM
> > To: Gavin Hu (Arm Technology China) <gavin...@arm.com>;
> dev@dpdk.org
> > Cc: nd <n...@arm.com>; tho...@monjalon.net; Richardson, Bruce
> > <bruce.richard...@intel.com>; Liu, Yong <yong....@intel.com>; Wang,
> Yinan
> > <yinan.w...@intel.com>; ajit.khapa...@broadcom.com;
> > somnath.ko...@broadcom.com; Honnappa Nagarahalli
> > <honnappa.nagaraha...@arm.com>; Ruifeng Wang (Arm Technology
> China)
> > <ruifeng.w...@arm.com>; Steve Capper <steve.cap...@arm.com>
> > Subject: RE: [dpdk-dev] [PATCH v2 1/5] net/i40e: use relaxed and remove
> > duplicate barrier
> >
> >
> >
> > > -----Original Message-----
> > > From: dev [mailto:dev-boun...@dpdk.org] On Behalf Of Gavin Hu
> > > Sent: Monday, September 16, 2019 7:27 PM
> > > To: dev@dpdk.org
> > > Cc: n...@arm.com; tho...@monjalon.net; Richardson, Bruce
> > > <bruce.richard...@intel.com>; Liu, Yong <yong....@intel.com>; Wang,
> > Yinan
> > > <yinan.w...@intel.com>; ajit.khapa...@broadcom.com;
> > > somnath.ko...@broadcom.com; honnappa.nagaraha...@arm.com;
> > > ruifeng.w...@arm.com; steve.cap...@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...@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. 
> >
> > Otherwise
> > Acked-by: Qi Zhang <qi.z.zh...@intel.com>
> >