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Date: Mon, 8 Jan 2024 14:42:11 -0800
From: Reinette Chatre <reinette.chatre@...el.com>
To: Maciej Wieczor-Retman <maciej.wieczor-retman@...el.com>, Fenghua Yu
<fenghua.yu@...el.com>, Shuah Khan <shuah@...nel.org>
CC: <ilpo.jarvinen@...ux.intel.com>, <linux-kernel@...r.kernel.org>,
<linux-kselftest@...r.kernel.org>
Subject: Re: [PATCH v2 4/4] selftests/resctrl: Add non-contiguous CBMs CAT
test
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@...el.com>
> ---
> 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.
> +
> + if (sparse_masks != ((ecx >> 3) & 1))
> + return -1;
Can a message be displayed to support the debugging this test failure?
> +
> + /* Write checks initialization. */
> + ret = get_full_cbm(test->resource, &full_cache_mask);
> + if (ret < 0)
> + return ret;
I assume this test failure relies on the error message from get_bit_mask()
that is called via get_full_cbm()?
> + bit_center = count_bits(full_cache_mask) / 2;
> + cont_mask = full_cache_mask >> bit_center;
> +
> + /* Contiguous mask write check. */
> + snprintf(schemata, sizeof(schemata), "%lx", cont_mask);
> + ret = write_schemata("", schemata, uparams->cpu, test->resource);
> + if (ret)
> + return ret;
How will user know what failed? I am seeing this single test exercise a few scenarios
and it is not obvious to me if the issue will be clear if this test,
noncont_cat_run_test(), fails.
> +
> + /*
> + * Non-contiguous mask write check. CBM has a 0xf hole approximately in the middle.
> + * Output is compared with support information to catch any edge case errors.
> + */
> + noncont_mask = ~(0xf << (bit_center - 2)) & full_cache_mask;
> + snprintf(schemata, sizeof(schemata), "%lx", noncont_mask);
> + ret = write_schemata("", schemata, uparams->cpu, test->resource);
> + if (ret && sparse_masks)
> + ksft_print_msg("Non-contiguous CBMs supported but write failed\n");
> + else if (ret && !sparse_masks)
> + ksft_print_msg("Non-contiguous CBMs not supported and write failed as expected\n");
> + else if (!ret && !sparse_masks)
> + ksft_print_msg("Non-contiguous CBMs not supported but write succeeded\n");
Can these messages be made more specific with a "write" changed to "write of
non-contiguous CBM"
> +
> + return !ret == !sparse_masks;
Please return negative on error. Ilpo just did a big cleanup to address this.
> +}
> +
> +static bool noncont_cat_feature_check(const struct resctrl_test *test)
> +{
> + if (!resctrl_resource_exists(test->resource))
> + return false;
> +
> + return resctrl_cache_feature_exists(test->resource, "sparse_masks");
> +}
> +
> struct resctrl_test l3_cat_test = {
> .name = "L3_CAT",
> .group = "CAT",
> @@ -299,3 +358,19 @@ struct resctrl_test l3_cat_test = {
> .feature_check = test_resource_feature_check,
> .run_test = cat_run_test,
> };
> +
> +struct resctrl_test l3_noncont_cat_test = {
> + .name = "L3_NONCONT_CAT",
> + .group = "CAT",
> + .resource = "L3",
> + .feature_check = noncont_cat_feature_check,
> + .run_test = noncont_cat_run_test,
> +};
> +
> +struct resctrl_test l2_noncont_cat_test = {
> + .name = "L2_NONCONT_CAT",
> + .group = "CAT",
> + .resource = "L2",
> + .feature_check = noncont_cat_feature_check,
> + .run_test = noncont_cat_run_test,
> +};
> diff --git a/tools/testing/selftests/resctrl/resctrl.h b/tools/testing/selftests/resctrl/resctrl.h
> index 74041a35d4ba..7b7a48d1fddd 100644
> --- a/tools/testing/selftests/resctrl/resctrl.h
> +++ b/tools/testing/selftests/resctrl/resctrl.h
> @@ -165,6 +165,7 @@ unsigned int count_contiguous_bits(unsigned long val, unsigned int *start);
> int get_full_cbm(const char *cache_type, unsigned long *mask);
> int get_mask_no_shareable(const char *cache_type, unsigned long *mask);
> int get_cache_size(int cpu_no, const char *cache_type, unsigned long *cache_size);
> +int get_cache_level(const char *cache_type);
> int read_info_res_file(const char *resource, const char *filename);
> void ctrlc_handler(int signum, siginfo_t *info, void *ptr);
> int signal_handler_register(void);
> @@ -201,5 +202,7 @@ extern struct resctrl_test mbm_test;
> extern struct resctrl_test mba_test;
> extern struct resctrl_test cmt_test;
> extern struct resctrl_test l3_cat_test;
> +extern struct resctrl_test l3_noncont_cat_test;
> +extern struct resctrl_test l2_noncont_cat_test;
>
> #endif /* RESCTRL_H */
> diff --git a/tools/testing/selftests/resctrl/resctrl_tests.c b/tools/testing/selftests/resctrl/resctrl_tests.c
> index 3044179ee6e9..f3dc1b9696e7 100644
> --- a/tools/testing/selftests/resctrl/resctrl_tests.c
> +++ b/tools/testing/selftests/resctrl/resctrl_tests.c
> @@ -19,6 +19,8 @@ static struct resctrl_test *resctrl_tests[] = {
> &mba_test,
> &cmt_test,
> &l3_cat_test,
> + &l3_noncont_cat_test,
> + &l2_noncont_cat_test,
> };
>
> static int detect_vendor(void)
> diff --git a/tools/testing/selftests/resctrl/resctrlfs.c b/tools/testing/selftests/resctrl/resctrlfs.c
> index 8546421f0940..8bd30973fec3 100644
> --- a/tools/testing/selftests/resctrl/resctrlfs.c
> +++ b/tools/testing/selftests/resctrl/resctrlfs.c
> @@ -100,7 +100,7 @@ int umount_resctrlfs(void)
> *
> * Return: cache level as integer or -1 if @cache_type is invalid.
> */
> -static int get_cache_level(const char *cache_type)
> +int get_cache_level(const char *cache_type)
> {
> if (!strcmp(cache_type, "L3"))
> return 3;
Reinette
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