Re: [dpdk-dev] [PATCH v1] net/memif: optimized with one-way barrier

["Phil Yang (Arm Technology China)" <Phil.Yang@arm.com>]

> -----Original Message-----
> From: Jakub Grajciar -X (jgrajcia - PANTHEON TECHNOLOGIES at Cisco)
> <jgrajcia@cisco.com>
> Sent: Tuesday, October 8, 2019 7:05 PM
> To: Phil Yang (Arm Technology China) <Phil.Yang@arm.com>; dev@dpdk.org
> Cc: thomas@monjalon.net; jerinj@marvell.com; Honnappa Nagarahalli
> <Honnappa.Nagarahalli@arm.com>; Damjan Marion (damarion)
> <damarion@cisco.com>; nd <nd@arm.com>; Gavin Hu (Arm Technology
> China) <Gavin.Hu@arm.com>; nd <nd@arm.com>
> Subject: RE: [dpdk-dev] [PATCH v1] net/memif: optimized with one-way
> barrier
> 
> > > -----Original Message-----
> > > From: dev <dev-bounces@dpdk.org> On Behalf Of Phil Yang
> > > Sent: Monday, August 26, 2019 7:00 PM
> > > To: jgrajcia@cisco.com; dev@dpdk.org
> > > Cc: thomas@monjalon.net; jerinj@marvell.com; Honnappa Nagarahalli
> > > <Honnappa.Nagarahalli@arm.com>; damarion@cisco.com; nd
> > <nd@arm.com>
> > > Subject: [dpdk-dev] [PATCH v1] net/memif: optimized with one-way
> > > barrier
> > >
> > > Using 'rte_mb' to synchronize the shared ring head/tail between
> > > producer and consumer will stall the pipeline and damage performance
> > > on the weak memory model platforms, such like aarch64. Meanwhile
> > > update the shared ring head and tail are observable and ordered
> between
> > CPUs on IA.
> > >
> > > Optimized this full barrier with the one-way barrier can improve the
> > > throughput. On aarch64 n1sdp server this patch make testpmd
> throughput
> > > boost 2.1%. On Intel E5-2640, testpmd got 3.98% performance gain.
> > >
> > > Signed-off-by: Phil Yang <phil.yang@arm.com>
> > > Reviewed-by: Gavin Hu <gavin.hu@arm.com>
> 
> The patch is looking good, but 'MEMIF_VERSION_MAJOR' in memif.h needs
> to
> be set to 3 as ring pointers are no longer volatile.

Updated in v2. 
Thanks for your comments.

Thanks,
Phil