[dpdk-dev] [PATCH v2] net/i40e: fix Rx instability with vector mode

Zhang, Qi Z qi.z.zhang at intel.com
Fri Oct 26 17:49:31 CEST 2018



> -----Original Message-----
> From: Richardson, Bruce
> Sent: Friday, October 26, 2018 6:12 AM
> To: Xing, Beilei <beilei.xing at intel.com>
> Cc: Zhang, Qi Z <qi.z.zhang at intel.com>; dev at dpdk.org; stable at dpdk.org
> Subject: Re: [dpdk-dev] [PATCH v2] net/i40e: fix Rx instability with vector
> mode
> 
> 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 at dpdk.org
> >
> > Signed-off-by: Beilei Xing <beilei.xing at intel.com>
> > ---
> >
> Do we not limit our descriptor ring sizes to powers of two anyway? 
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 configure, 
and I guess a more flexible queue size configure may help on the platform that have limited cache?




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