linux-kernel - Re: [PATCH v2] selftests/resctrl: Fix noncont_cat_run

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Date: Mon, 10 Jun 2024 12:51:25 -0500
From: "Moger, Babu" <babu.moger@....com>
To: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
Cc: fenghua.yu@...el.com, Reinette Chatre <reinette.chatre@...el.com>,
 shuah@...nel.org, LKML <linux-kernel@...r.kernel.org>,
 linux-kselftest@...r.kernel.org,
 Maciej Wieczór-Retman <maciej.wieczor-retman@...el.com>,
 peternewman@...gle.com, eranian@...gle.com
Subject: Re: [PATCH v2] selftests/resctrl: Fix noncont_cat_run_test for AMD

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@....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