Hi Reinette,
On 6/6/2024 6:58 PM, Reinette Chatre wrote:
Hi Babu,
On 6/6/24 4:09 PM, Moger, Babu wrote:
Hi Reinette,
On 6/6/2024 3:33 PM, Reinette Chatre wrote:
Hi Babu,
On 6/5/24 2:36 PM, Babu Moger wrote:
The selftest noncont_cat_run_test fails on AMD with the warnings. Reason is, AMD supports non contiguous CBM masks but does not report it via CPUID.
Update noncont_cat_run_test to check for the vendor when verifying CPUID.
Fixes: ae638551ab64 ("selftests/resctrl: Add non-contiguous CBMs CAT test") Signed-off-by: Babu Moger babu.moger@amd.com
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 | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/testing/selftests/resctrl/cat_test.c b/tools/testing/selftests/resctrl/cat_test.c index d4dffc934bc3..b2988888786e 100644 --- a/tools/testing/selftests/resctrl/cat_test.c +++ b/tools/testing/selftests/resctrl/cat_test.c @@ -308,7 +308,7 @@ static int noncont_cat_run_test(const struct resctrl_test *test, else return -EINVAL; - if (sparse_masks != ((ecx >> 3) & 1)) { + if ((get_vendor() == ARCH_INTEL) && sparse_masks != ((ecx >> 3) & 1)) { ksft_print_msg("CPUID output doesn't match 'sparse_masks' file content!\n"); return 1; }
Since AMD does not report this support via CPUID it does not seem appropriate to use CPUID at all on AMD when doing the hardware check. I think the above check makes it difficult to understand what is different on AMD.
What if instead there is a new function, for example, "static bool arch_supports_noncont_cat(const struct resctrl_test *test)" that returns true if the hardware supports non-contiguous CBM?
Sure.
The vendor check can be in there to make it obvious what is going on:
/* AMD always supports non-contiguous CBM. */ if (get_vendor() == AMD) return true;
/* CPUID check for Intel here. */
The "sparse_masks" from kernel can then be checked against hardware support with an appropriate (no mention of CPUID) error message if this fails.
Something like this?
diff --git a/tools/testing/selftests/resctrl/cat_test.c b/tools/testing/selftests/resctrl/cat_test.c index d4dffc934bc3..b75d220f29f6 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; + } else {
The else can be dropped since it follows a return.
Sure
The rest of the code can be prefixed with a matching comment like: /* Intel support for non-contiguous CBM needs to be discovered. */
Sure
(please feel free to improve)
+ 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 does not support non-contiguous CBM!\n");
Please fix the test as well as the message. It is not an error if hardware does not support non-contiguous CBM. It is an error if the hardware and kernel disagrees whether non-contiguous CBM is supported.
Not sure about this comment.
Did you mean?
if (!arch_supports_noncont_cat(test)) { ksft_print_msg("Hardware does not support non-contiguous CBM!\n"); return 0; } else if (arch_supports_noncont_cat(test) && !sparse_masks)) { ksft_print_msg("Hardware and kernel support for non-contiguous CBM does not match!\n"); return 1; }