Re: [PATCH net-next v2 1/2] selftests/ptr_ring: add benchmark application for ptr_ring

[Yunsheng Lin <linyunsheng@huawei.com>]

On 2021/6/25 11:36, Jason Wang wrote:
> 
> 在 2021/6/25 上午11:18, Yunsheng Lin 写道:
>> Currently ptr_ring selftest is embedded within the virtio
>> selftest, which involves some specific virtio operation,
>> such as notifying and kicking.
>>
>> As ptr_ring has been used by various subsystems, it deserves
>> it's owner's selftest in order to benchmark different usecase
>> of ptr_ring, such as page pool and pfifo_fast qdisc.
>>
>> So add a simple application to benchmark ptr_ring performance.
>> Currently two test mode is supported:
>> Mode 0: Both enqueuing and dequeuing is done in a single thread,
>>          it is called simple test mode in the test app.
>> Mode 1: Enqueuing and dequeuing is done in different thread
>>          concurrently, also known as SPSC(single-producer/
>>          single-consumer) test.
>>
>> The multi-producer/single-consumer test for pfifo_fast case is
>> not added yet, which can be added if using CAS atomic operation
>> to enable lockless multi-producer is proved to be better than
>> using r->producer_lock.
>>
>> Only supported on x86 and arm64 for now.
>>
>> Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
>> ---
>>   MAINTAINERS                                      |   5 +
>>   tools/testing/selftests/ptr_ring/Makefile        |   6 +
>>   tools/testing/selftests/ptr_ring/ptr_ring_test.c | 249 +++++++++++++++++++++++
>>   tools/testing/selftests/ptr_ring/ptr_ring_test.h | 150 ++++++++++++++
>>   4 files changed, 410 insertions(+)
> 
> 
> Why can't you simply reuse tools/virtio/ringtest?

The main reason is stated in the commit log:
"Currently ptr_ring selftest is embedded within the virtio
selftest, which involves some specific virtio operation,
such as notifying and kicking.

As ptr_ring has been used by various subsystems, it deserves
it's owner's selftest in order to benchmark different usecase
of ptr_ring, such as page pool and pfifo_fast qdisc."

More specificly in tools/virtio/ringtest/main.c and
tools/virtio/ringtest/ptr_ring.c, there are a lot of operation
related to virtio usecase, such as start_guest(), start_host(),
poll_used(), notify() or kick() ....., so it makes more sense
to add a generic selftest for ptr ring as it is not only used
by virtio now.


> 
> Thanks
> 
> 
> .
>