On 2021/6/27 14:09, Michael S. Tsirkin wrote:
On Fri, Jun 25, 2021 at 11:52:16AM +0800, Yunsheng Lin wrote:
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.
Okay that answers why you didn't just run main.c but why not add a new test under tools/virtio/ringtest/ reusing the rest of infrastructure that you currently copied?
Actually, my first attempt was to reuse the infrastructure in tools/virtio/ or tools/virtio/ringtest/, and neither of them was able to be compiled in the latest kernel.
And then I read through the code to try fixing the compile error, I found that the testcase under tools/virtio/ is coupled deeply to virtio as explained above, which was difficult to read for someone who is not fimiliar with virtio.
So I searched for how testing is supposed to be added in the kernel, it seems it is more common to add the testing in tools/testing or tools/testing/selftest, and ptr ring is not only used by virtio now, so it seems more appropriate to add a sperate testing for virtio by instinct.
Most of tools/virtio/ is to do testing related to virtio testing, IMHO, most of them are better to be in tools/testing/selftest. Even if most of virtio testing is moved to tools/testing/selftest, I think it makes more sense to decouple the virtio testing to ptr_ring testing too if we can find some mechanism to share the abstract infrastructure in ptr_ring_test.h for both virtio and ptr_ring testing.
Thanks
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