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Date: Thu, 4 Dec 2014 14:03:24 +0000
From: Bruce Richardson <bruce.richardson@intel.com>
To: Thomas Monjalon <thomas.monjalon@6wind.com>
Message-ID: <20141204140324.GA4828@bricha3-MOBL3>
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Organization: Intel Shannon Ltd.
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Cc: dev@dpdk.org
Subject: Re: [dpdk-dev] [PATCH] examples: fix symmetric_mp,
 set NIC rx_drop_en bit
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On Thu, Dec 04, 2014 at 02:37:15PM +0100, Thomas Monjalon wrote:
> 2014-12-03 16:56, Bruce Richardson:
> > The symmetric_mp example app is set up to allow two processes to
> > share a NIC port, with each pulling packets from one queue. In order
> > to have the app continue working when one of the process dies, the
> > drop_en bit should be set in the NIC configuration. Without this bit
> > set, the NIC will stall once any queue fills. With the bit set, once
> > a queue fills, all subsequent packets for that queue are discarded
> > allowing other queues to continue operating as normal.
> > 
> > This setting was missed when converting to use standardised defaults
> > in commit 81f7ecd9.
> 
> I don't see rx_drop_en in commit 81f7ecd9.
> Why do you say it was missed?
>
This is the one app that needs the drop_en bit set, and the bit is not set in the
defaults. Therefore, when this app was converted to use the defaults from the
driver, the drop_en bit should have been explicitly set as in this patch. [The 
fact of there being no drop_en bit in the commit is proof of its absense :-)].

/Bruce