Re: [PATCH v2] selftests/resctrl: Fix noncont_cat_run_test for AMD

Moger, Babu
2024-06-10T17:51:30Z

Hi

On 6/10/24 11:20, Ilpo Järvinen wrote:
> On Mon, 10 Jun 2024, Babu Moger wrote:
>
>> The selftest noncont_cat_run_test fails on AMD with the warnings. Reason
>
> noncont_cat_run_test()

I want to mention the test here. not function. How about this?

"The selftest non-contiguous CBM test fails on AMD with the warnings."

>
> (In general, use () when refering to a function, same thing in the
> shortlog).
>
> "the warnings" sounds like I should know about what warning it fails with
> but there's no previous context which tells that information. I suggest
> you either use "a warning" or quote the warning it fails with into the
> commit message.
>
>> is, AMD supports non contiguous CBM masks but does not report it via CPUID.
>
> non-contiguous

Sure.

>
>> Update noncont_cat_run_test to check for the vendor when verifying CPUID.
>
> ()

Sure.

>
>> Fixes: ae638551ab64 ("selftests/resctrl: Add non-contiguous CBMs CAT test")
>> Signed-off-by: Babu Moger <babu.moger@amd.com>
>> ---
>> v2: Moved the non contiguous verification to a new function
>> arch_supports_noncont_cat.
>>
>> v1:
>> This was part of the series
>> https://lore.kernel.org/lkml/cover.1708637563.git.babu.moger@amd.com/
>> Sending this as a separate fix per review comments.
>> ---
>> tools/testing/selftests/resctrl/cat_test.c | 32 +++++++++++++++-------
>> 1 file changed, 22 insertions(+), 10 deletions(-)
>>
>> diff --git a/tools/testing/selftests/resctrl/cat_test.c b/tools/testing/selftests/resctrl/cat_test.c
>> index d4dffc934bc3..742782438ca3 100644
>> --- a/tools/testing/selftests/resctrl/cat_test.c
>> +++ b/tools/testing/selftests/resctrl/cat_test.c
>> @@ -288,11 +288,30 @@ static int cat_run_test(const struct resctrl_test *test, const struct user_param
>> return ret;
>> }
>>
>> +static bool arch_supports_noncont_cat(const struct resctrl_test *test)
>> +{
>> + unsigned int eax, ebx, ecx, edx;
>> +
>> + /* AMD always supports non-contiguous CBM. */
>> + if (get_vendor() == ARCH_AMD)
>> + return true;
>> +
>> + /* Intel support for non-contiguous CBM needs to be discovered. */
>> + if (!strcmp(test->resource, "L3"))
>> + __cpuid_count(0x10, 1, eax, ebx, ecx, edx);
>> + else if (!strcmp(test->resource, "L2"))
>> + __cpuid_count(0x10, 2, eax, ebx, ecx, edx);
>> + else
>> + return false;
>> +
>> + return ((ecx >> 3) & 1);
>> +}
>> +
>> 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, sparse_masks;
>> + unsigned int sparse_masks;
>> int bit_center, ret;
>> char schemata[64];
>>
>> @@ -301,15 +320,8 @@ static int noncont_cat_run_test(const struct resctrl_test *test,
>> if (ret)
>> return ret;
>>
>> - if (!strcmp(test->resource, "L3"))
>> - __cpuid_count(0x10, 1, eax, ebx, ecx, edx);
>> - else if (!strcmp(test->resource, "L2"))
>> - __cpuid_count(0x10, 2, eax, ebx, ecx, edx);
>> - else
>> - return -EINVAL;
>> -
>> - if (sparse_masks != ((ecx >> 3) & 1)) {
>> - ksft_print_msg("CPUID output doesn't match 'sparse_masks' file content!\n");
>> + if (arch_supports_noncont_cat(test) != sparse_masks) {
>> + ksft_print_msg("Hardware and kernel differ on non-contiguous CBM support!\n");
>> return 1;
>
> This looks better than the previous version, thanks.

Thanks.
Babu Moger