Re: [dpdk-dev] [PATCH v2] net/virtio: fix AVX512 datapath selection

["Liu, Yong" <yong.liu@intel.com>]

> -----Original Message-----
> From: Maxime Coquelin <maxime.coquelin@redhat.com>
> Sent: Tuesday, May 12, 2020 3:50 AM
> To: Yigit, Ferruh <ferruh.yigit@intel.com>; Wang, Zhihong
> <zhihong.wang@intel.com>; Ye, Xiaolong <xiaolong.ye@intel.com>; Liu,
> Yong <yong.liu@intel.com>
> Cc: dev@dpdk.org; Thomas Monjalon <thomas@monjalon.net>; David
> Marchand <david.marchand@redhat.com>; Richardson, Bruce
> <bruce.richardson@intel.com>; Nicolau, Radu <radu.nicolau@intel.com>;
> Luca Boccassi <bluca@debian.org>
> Subject: Re: [PATCH v2] net/virtio: fix AVX512 datapath selection
> 
> 
> 
> On 5/11/20 8:48 PM, Ferruh Yigit wrote:
> > From: Maxime Coquelin <maxime.coquelin@redhat.com>
> >
> > The AVX512 packed ring datapath selection was only done
> > at build time, but it should also be checked at runtime
> > that the CPU supports it.
> >
> > This patch add a CPU flags check so that non-vectorized
> > path is selected at runtime if AVX512 is not supported.
> >
> > Also in meson build enable vectorization only for relevant file, not for
> > all driver.
> >
> > Fixes: ccb10995c2ad ("net/virtio: add election for vectorized path")
> >
> > Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
> > Signed-off-by: Ferruh Yigit <ferruh.yigit@intel.com>
> > ---
> > Cc: Bruce Richardson <bruce.richardson@intel.com>
> > Cc: Radu Nicolau <radu.nicolau@intel.com>
> > Cc: Luca Boccassi <bluca@debian.org>
> >
> > For meson I mainly adapted implementation from other driver, not able
> to
> > test or verify myself.
> > ---
> >  drivers/net/virtio/meson.build     | 9 +++++++--
> >  drivers/net/virtio/virtio_ethdev.c | 6 ++++--
> >  2 files changed, 11 insertions(+), 4 deletions(-)
> 
> Thanks Ferruh, I cannot test either right now but it looks good to me:
> 

Hi Maxime & Ferruh,
IMHO, meson build update is the essential part for fixing unexpected AVX512 instructions. 
Change in virtio_ethdev may cause building issues on ppc and arm platform.  Is it convenient to revert that change?

Regards,
Marvin

> In case you're waiting for it:
> Acked-by: Maxime Coquelin <maxime.coquelin@redhat.com>
> 
> Maxime