Hi Ilpo,
On 1/9/2024 1:13 AM, Ilpo Järvinen wrote:
> On Mon, 8 Jan 2024, Reinette Chatre wrote:
>
>> Hi Maciej,
>>
>> On 12/12/2023 6:52 AM, Maciej Wieczor-Retman wrote:
>>> Add tests for both L2 and L3 CAT to verify the return values
>>> generated by writing non-contiguous CBMs don't contradict the
>>> reported non-contiguous support information.
>>>
>>> Use a logical XOR to confirm return value of write_schemata() and
>>> non-contiguous CBMs support information match.
>>>
>>> Signed-off-by: Maciej Wieczor-Retman <maciej.wieczor-retman@xxxxxxxxx>
>>> ---
>>> Changelog v2:
>>> - Redo the patch message. (Ilpo)
>>> - Tidy up __cpuid_count calls. (Ilpo)
>>> - Remove redundant AND in noncont_mask calculations (Ilpo)
>>> - Fix bit_center offset.
>>> - Add newline before function return. (Ilpo)
>>> - Group non-contiguous tests with CAT tests. (Ilpo)
>>> - Use a helper for reading sparse_masks file. (Ilpo)
>>> - Make get_cache_level() available in other source files. (Ilpo)
>>>
>>> tools/testing/selftests/resctrl/cat_test.c | 75 +++++++++++++++++++
>>> tools/testing/selftests/resctrl/resctrl.h | 3 +
>>> .../testing/selftests/resctrl/resctrl_tests.c | 2 +
>>> tools/testing/selftests/resctrl/resctrlfs.c | 2 +-
>>> 4 files changed, 81 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/tools/testing/selftests/resctrl/cat_test.c b/tools/testing/selftests/resctrl/cat_test.c
>>> index 7dc7206b3b99..ecf553a89aae 100644
>>> --- a/tools/testing/selftests/resctrl/cat_test.c
>>> +++ b/tools/testing/selftests/resctrl/cat_test.c
>>> @@ -292,6 +292,65 @@ static int cat_run_test(const struct resctrl_test *test, const struct user_param
>>> return ret;
>>> }
>>>
>>> +static int noncont_cat_run_test(const struct resctrl_test *test,
>>> + const struct user_params *uparams)
>>> +{
>>> + unsigned long full_cache_mask, cont_mask, noncont_mask;
>>> + unsigned int eax, ebx, ecx, edx, ret;
>>> + int level, bit_center, sparse_masks;
>>> + char schemata[64];
>>> +
>>> + /* Check to compare sparse_masks content to cpuid output. */
>>
>> "cpuid" -> "CPUID" (to note it is an instruction)
>>
>>> + sparse_masks = read_info_res_file(test->resource, "sparse_masks");
>>> + if (sparse_masks < 0)
>>> + return sparse_masks;
>>> +
>>> + level = get_cache_level(test->resource);
>>> + if (level < 0)
>>> + return -EINVAL;
>>> + __cpuid_count(0x10, 4 - level, eax, ebx, ecx, edx);
>>
>> Please do not invent relationships. Please replace the "4 - level" with
>> specific index used that depends on particular cache. The cache level
>> may not even be needed, just use the resource to determine the correct
>> index.
>
> This is actually my fault, I suggested Maciej could use arithmetics there.
No problem. The math works for the current values but there is no such
relationship. If hypothetically a new cache level needs to be supported
then this computation cannot be relied upon to continue to be correct.
>>> + return !ret == !sparse_masks;
>>
>> Please return negative on error. Ilpo just did a big cleanup to address this.
>
> Test failure is not same as an error. So tests should return negative for
> errors which prevent even running test at all, and 0/1 for test
> success/fail.
>
Thanks for catching this. I missed this subtlety in the framework.
Reinette
