On 2021/7/2 14:43, Jason Wang wrote:
>
> 在 2021/7/1 下午8:26, 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 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 producing and consuming is done in a single thread,
>> it is called simple test mode in the test app.
>> Mode 1: Producing and consuming 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.
>>
>> Signed-off-by: Yunsheng Lin <linyunsheng@xxxxxxxxxx>
>> ---
>> V3: Remove timestamp sampling, use standard C library as much
>> as possible.
[...]
>> +static void *produce_worker(void *arg)
>> +{
>> + struct worker_info *info = arg;
>> + unsigned long i = 0;
>> + int ret;
>> +
>> + while (++i <= info->test_count) {
>> + while (__ptr_ring_full(&ring))
>> + cpu_relax();
>> +
>> + ret = __ptr_ring_produce(&ring, (void *)i);
>> + if (ret) {
>> + fprintf(stderr, "produce failed: %d\n", ret);
>> + info->error = true;
>> + return NULL;
>> + }
>> + }
>> +
>> + info->error = false;
>> +
>> + return NULL;
>> +}
>> +
>> +static void *consume_worker(void *arg)
>> +{
>> + struct worker_info *info = arg;
>> + unsigned long i = 0;
>> + int *ptr;
>> +
>> + while (++i <= info->test_count) {
>> + while (__ptr_ring_empty(&ring))
>> + cpu_relax();
>
>
> Any reason for not simply use __ptr_ring_consume() here?
No particular reason, just to make sure the ring is
non-empty before doing the enqueuing, we could check
if the __ptr_ring_consume() return NULL to decide
the if the ring is empty. Using __ptr_ring_consume()
here enable testing the correctness and performance of
__ptr_ring_consume() too.
>
>
>> +
>> + ptr = __ptr_ring_consume(&ring);
>> + if ((unsigned long)ptr != i) {
>> + fprintf(stderr, "consumer failed, ptr: %lu, i: %lu\n",
>> + (unsigned long)ptr, i);
>> + info->error = true;
>> + return NULL;
>> + }
>> + }
>> +
>> + if (!__ptr_ring_empty(&ring)) {
>> + fprintf(stderr, "ring should be empty, test failed\n");
>> + info->error = true;
>> + return NULL;
>> + }
>> +
>> + info->error = false;
>> + return NULL;
>> +}
>> +
[...]
>> +
>> + return 0;
>> +}
>> diff --git a/tools/testing/selftests/ptr_ring/ptr_ring_test.h b/tools/testing/selftests/ptr_ring/ptr_ring_test.h
>> new file mode 100644
>> index 0000000..32bfefb
>> --- /dev/null
>> +++ b/tools/testing/selftests/ptr_ring/ptr_ring_test.h
>
>
> Let's reuse ptr_ring.c in tools/virtio/ringtest. Nothing virt specific there.
It *does* have some virtio specific at the end of ptr_ring.c.
It can be argued that the ptr_ring.c in tools/virtio/ringtest
could be refactored to remove the function related to virtio.
But as mentioned in the previous disscusion [1], the tools/virtio/
seems to have compile error in the latest kernel, it does not seems
right to reuse that. And most of testcase in tools/virtio/ seems
better be in tools/virtio/ringtest instead，so until the testcase
in tools/virtio/ is compile-error-free and moved to tools/testing/
selftests/, it seems better not to reuse it for now.
1. https://patchwork.kernel.org/project/netdevbpf/patch/1624591136-6647-2-git-send-email-linyunsheng@xxxxxxxxxx/#24278945
>
> Thanks
>
[...]
>
> .
>
