[dpdk-dev] [PATCH] net/mlx5: fix Tx doorbell

Ferruh Yigit ferruh.yigit at intel.com
Thu Jan 5 19:17:06 CET 2017


On 1/5/2017 6:12 PM, Adrien Mazarguil wrote:
> On Thu, Jan 05, 2017 at 05:01:27PM +0000, Ferruh Yigit wrote:
>> On 1/5/2017 4:52 PM, Adrien Mazarguil wrote:
>>> On Thu, Jan 05, 2017 at 05:32:26PM +0100, Adrien Mazarguil wrote:
>>>> Hi Ferruh,
>>>>
>>>> On Thu, Jan 05, 2017 at 03:19:35PM +0000, Ferruh Yigit wrote:
>>>>> On 12/9/2016 1:27 PM, Nelio Laranjeiro wrote:
>>>>>> Too much data is uselessly written to the Tx doorbell.
>>>>>>
>>>>>> Fixes: 1d88ba171942 ("net/mlx5: refactor Tx data path")
>>>>>>
>>>>>> Signed-off-by: Nelio Laranjeiro <nelio.laranjeiro at 6wind.com>
>>>>>> Acked-by: Adrien Mazarguil <adrien.mazarguil at 6wind.com>
>>>>>>
>>>>>
>>>>> Applied to dpdk-next-net/master, thanks.
>>>>>
>>>>> Is not CC'ing stable intentional, since this patch depends on a patch
>>>>> introduced in this release? If not intentional, please CC stable.
>>>>
>>>> I intended to update the commit message for this patch as in the meantime we
>>>> discovered it addresses a significant regression introduced in v16.11.
>>>>
>>>> CC'ing stable now.
>>>>
>>>> If possible, can you amend the commit log with:
>>>>
>>>> ---
>>>>
>>>> net/mlx5: fix Tx doorbell
>>>>
>>>> Too much data is uselessly written to the Tx doorbell, which since v16.11
>>>> may also cause Tx queues to behave erratically and crash applications.
>>>>
>>>> This regression was seen on VF devices when the BlueFlame buffer size is
>>>> zero (txq->cqe_n == 0) due to the following change:
>>>>
>>>>  -       cqe = &(*txq->cqes)[ci & (txq->cqe_n - 1)].cqe64;
>>>>  +       cqe = &(*txq->cqes)[ci & ((1 << txq->cqe_n) - 1)];
>>>>
>>>> Fixes: 1d88ba171942 ("net/mlx5: refactor Tx data path")
>>>> Fixes: e2f116ee3cac ("net/mlx5: reduce memory overhead for CQE handling")
>>>>
>>>> Signed-off-by: Nelio Laranjeiro <nelio.laranjeiro at 6wind.com>
>>>> Acked-by: Adrien Mazarguil <adrien.mazarguil at 6wind.com>
>>>> Cc: stable at dpdk.org
>>>>
>>>> ---
>>>
>>> I mixed the commit that introduced the regression with a similar looking yet
>>> harmless one, here is the proper message to use, sorry for the noise:
>>>
>>> ---
>>>
>>> net/mlx5: fix Tx doorbell
>>>
>>> Too much data is uselessly written to the Tx doorbell, which since v16.11
>>> may also cause Tx queues to behave erratically and crash applications.
>>>
>>> This regression was seen on VF devices when the BlueFlame buffer size is
>>> zero (txq->bf_buf_size) due to the following change:
>>>
>>>  -       txq->bf_offset ^= txq->bf_buf_size;
>>>  +       txq->bf_offset ^= (1 << txq->bf_buf_size);
>>>
>>> Fixes: 1d88ba171942 ("net/mlx5: refactor Tx data path")
>>> Fixes: d5793daefec8 ("net/mlx5: reduce memory overhead for BF handling")
>>>
>>> Signed-off-by: Nelio Laranjeiro <nelio.laranjeiro at 6wind.com>
>>> Acked-by: Adrien Mazarguil <adrien.mazarguil at 6wind.com>
>>> Cc: stable at dpdk.org
>>>
>>> ---
>>>
>>
>> Can you please confirm commit in latest next-net?
> 
> Not sure if the "Cc: stable at dpdk.org" line should have been kept, 

No, we are removing it from the commit.
It is useful in the patch since "git send-email" ensures the stable mail
list is added into CC.
But it is not that useful in the git history.

> otherwise it's perfect, thanks Ferruh!

OK, thanks.

> 




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