[dpdk-dev] [PATCH RFC 4/4] doc: add note about rte_vhost_enqueue_burst thread safety.

[Xie, Huawei]

On 2/19/2016 5:05 PM, Ilya Maximets wrote:
> On 19.02.2016 11:36, Xie, Huawei wrote:
>> On 2/19/2016 3:10 PM, Yuanhan Liu wrote:
>>> On Fri, Feb 19, 2016 at 09:32:43AM +0300, Ilya Maximets wrote:
>>>> Signed-off-by: Ilya Maximets <i.maximets at samsung.com>
>>>> ---
>>>>  doc/guides/prog_guide/thread_safety_dpdk_functions.rst | 1 +
>>>>  1 file changed, 1 insertion(+)
>>>>
>>>> diff --git a/doc/guides/prog_guide/thread_safety_dpdk_functions.rst b/doc/guides/prog_guide/thread_safety_dpdk_functions.rst
>>>> index 403e5fc..13a6c89 100644
>>>> --- a/doc/guides/prog_guide/thread_safety_dpdk_functions.rst
>>>> +++ b/doc/guides/prog_guide/thread_safety_dpdk_functions.rst
>>>> @@ -67,6 +67,7 @@ then locking, or some other form of mutual exclusion, is necessary.
>>>>  The ring library is based on a lockless ring-buffer algorithm that maintains its original design for thread safety.
>>>>  Moreover, it provides high performance for either multi- or single-consumer/producer enqueue/dequeue operations.
>>>>  The mempool library is based on the DPDK lockless ring library and therefore is also multi-thread safe.
>>>> +rte_vhost_enqueue_burst() is also thread safe because based on lockless ring-buffer algorithm like the ring library.
>>> FYI, Huawei meant to make rte_vhost_enqueue_burst() not be thread-safe,
>>> to aligh with the usage of rte_eth_tx_burst().
>>>
>>> 	--yliu
>> I have a patch to remove the lockless enqueue. Unless there is strong
>> reason, i prefer vhost PMD to behave like other PMDs, with no internal
>> lockless algorithm. In future, for people who really need it, we could
>> have dynamic/static switch to enable it.

Thomas, what is your opinion on this and my patch removing lockless enqueue?

> OK, got it. So, I think, this documentation patch may be dropped.
> Other patches of series still may be merged to fix existing issues and
> keep code in consistent state for the future.
> Am I right?

Yes.

> Best regards, Ilya Maximets.
>