Re: [PATCH v3 bpf-next] selftests/bpf: Add parallelism to test_progs

[Yonghong Song <yhs@fb.com>]

On 9/10/21 11:53 AM, sunyucong@gmail.com wrote:
> On Fri, Sep 10, 2021 at 2:28 PM Yonghong Song <yhs@fb.com> wrote:
>>
>>
>>
>> On 9/9/21 12:35 PM, Yucong Sun wrote:
>>> From: Yucong Sun <sunyucong@gmail.com>
>>>
>>> This patch adds "-j" mode to test_progs, executing tests in multiple process.
>>> "-j" mode is optional, and works with all existing test selection mechanism, as
>>> well as "-v", "-l" etc.
>>>
>>> In "-j" mode, main process use UDS/DGRAM to communicate to each forked worker,
>>> commanding it to run tests and collect logs. After all tests are finished, a
>>> summary is printed. main process use multiple competing threads to dispatch
>>> work to worker, trying to keep them all busy.
>>>
>>> Example output:
>>>
>>>     > ./test_progs -n 15-20 -j
>>>     [    8.584709] bpf_testmod: loading out-of-tree module taints kernel.
>>>     Launching 2 workers.
>>>     [0]: Running test 15.
>>>     [1]: Running test 16.
>>>     [1]: Running test 17.
>>>     [1]: Running test 18.
>>>     [1]: Running test 19.
>>>     [1]: Running test 20.
>>>     [1]: worker exit.
>>>     [0]: worker exit.
>>>     #15 btf_dump:OK
>>>     #16 btf_endian:OK
>>>     #17 btf_map_in_map:OK
>>>     #18 btf_module:OK
>>>     #19 btf_skc_cls_ingress:OK
>>>     #20 btf_split:OK
>>>     Summary: 6/20 PASSED, 0 SKIPPED, 0 FAILED
>>
>> I tried the patch with latest bpf-next and
>>
>> https://lore.kernel.org/bpf/20210909215658.hgqkvxvtjrvdnrve@revolver/T/#u
>> to avoid kernel warning.
>>
>> My commandline is ./test_progs -j
>> my env is a 4 cpu qemu.
>> It seems the test is stuck and cannot finish:
>> ...
>> Still waiting for thread 0 (test 0).
>>
>>
>> Still waiting for thread 0 (test 0).
>>
>>
>> Still waiting for thread 0 (test 0).
>>
>>
>> Still waiting for thread 0 (test 0).
>>
>>
>> Still waiting for thread 0 (test 0).
>>
>>
>>
>>
>>
>> [1]+  Stopped                 ./test_progs -j
> 
> Sorry, It seems I forgot to test without "-n" param,  here is a
> trivial patch that will make it work.
> 
> diff --git a/tools/testing/selftests/bpf/test_progs.c
> b/tools/testing/selftests/bpf/test_progs.c
> index 74c6ea45502d..dd7bb2bec4d4 100644
> --- a/tools/testing/selftests/bpf/test_progs.c
> +++ b/tools/testing/selftests/bpf/test_progs.c
> @@ -780,7 +780,7 @@ void crash_handler(int signum)
>          backtrace_symbols_fd(bt, sz, STDERR_FILENO);
>   }
> 
> -int current_test_idx = -1;
> +int current_test_idx = 0;
>   pthread_mutex_t current_test_lock;
> 
>   struct test_result {

Indeed. With this change the './test_progs -j' finished
although I saw some test failures which is also mentioned
in the patch itself.

> 
> 
> Cheers.
>