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From: Ferruh Yigit <ferruh.yigit@intel.com>
To: <heinrich.kuhn@corigine.com>, <dev@dpdk.org>
Cc: <stable@dpdk.org>, Simon Horman <simon.horman@corigine.com>
Subject: Re: [dpdk-dev] [dpdk-stable] [PATCH] net/nfp: fix minimum descriptor sizes
Date: Tue, 31 Aug 2021 16:57:21 +0100	[thread overview]
Message-ID: <5f9c47ae-e0a6-4bb8-4889-0b1d75611318@intel.com> (raw)
In-Reply-To: <20210823075921.97168-1-heinrich.kuhn@corigine.com>

On 8/23/2021 8:59 AM, heinrich.kuhn@corigine.com wrote:
> From: Heinrich Kuhn <heinrich.kuhn@corigine.com>
> 
> The NFP4000/6000 supports a minimum of 256 Tx/Rx descriptors and not 64.
> Before this patch when a DPDK application configured < 256 Tx
> descriptors the hardware read/write pointers would be unmasked and not
> wrapped at the expected size of the ring. The PMD logic to determine the
> amount of free space in the Tx ring is incompatible with the unmasked
> hwqueue pointers and this will result in the PMD not updating the
> read pointer at all.The knock-on effect is that under high load the
> PMD will potentially re-use a Tx descriptor before the hw has had a
> chance to process that particular descriptor. This issue can manifest as
> a DMA error when the hardware tries to perform a DMA with info from a
> partially populated descriptor.
> 
> Fixes: defb9a5dd156 ("nfp: introduce driver initialization")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Heinrich Kuhn <heinrich.kuhn@corigine.com>
> Signed-off-by: Simon Horman <simon.horman@corigine.com>

Applied to dpdk-next-net/main, thanks.

      reply	other threads:[~2021-08-31 15:57 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-23  7:59 [dpdk-dev] " heinrich.kuhn
2021-08-31 15:57 ` Ferruh Yigit [this message]

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