From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Zhang, Qi Z" <qi.z.zhang@intel.com>
Subject: Re: [PATCH v2] net/i40e: fix Rx instability with vector
 mode
Date: Fri, 26 Oct 2018 15:49:31 +0000
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To: "Richardson, Bruce" <bruce.richardson@intel.com>, "Xing, Beilei"
 <beilei.xing@intel.com>
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> -----Original Message-----
> From: Richardson, Bruce
> Sent: Friday, October 26, 2018 6:12 AM
> To: Xing, Beilei <beilei.xing@intel.com>
> Cc: Zhang, Qi Z <qi.z.zhang@intel.com>; dev@dpdk.org; stable@dpdk.org
> Subject: Re: [dpdk-dev] [PATCH v2] net/i40e: fix Rx instability with vect=
or
> mode
>=20
> On Fri, Oct 26, 2018 at 02:33:27PM +0800, Beilei Xing wrote:
> > Previously, there is instability during vector Rx if descriptor number
> > is not power of 2, e.g. process hang and some Rx packets are
> > unexpectedly empty. That's because vector Rx mode assumes Rx
> > descriptor number is power of 2 when doing bit mask.
> > This patch allows vector mode only when the number of Rx descriptor is
> > power of 2.
> >
> > Fixes: 8e109464c022 ("i40e: allow vector Rx and Tx usage")
> > Fixes: a3c83a2527e1 ("net/i40e: enable runtime queue setup")
> > Cc: stable@dpdk.org
> >
> > Signed-off-by: Beilei Xing <beilei.xing@intel.com>
> > ---
> >
> Do we not limit our descriptor ring sizes to powers of two anyway?=20
Is there a
> real need for non-power-of-2 ring sizes?

This is tracked by some Bugzilla, seems someone is using this kind of confi=
gure,=20
and I guess a more flexible queue size configure may help on the platform t=
hat have limited cache?