Hi Ilpo,
On 8/8/2023 2:16 AM, Ilpo Järvinen wrote:
> Benchmark parameter uses fixed-size buffers in stack which is slightly
> dangerous. As benchmark command is used in multiple tests, it should
Could you please be specific with issues with current implementation?
The term "slightly dangerous" is vague.
> not be mutated by the tests. Due to the order of tests, mutating the
> span argument in CMT test does not trigger any real problems currently.
>
> Mark benchmark_cmd strings as const and setup the benchmark command
> using pointers. As span is constant in main(), just provide the default
> span also as string to be used in setting up the default fill_buf
> argument so no malloc() is required for it.
What is wrong with using malloc()?
>
> CMT test has to create a copy of the benchmark command before altering
> the benchmark command.
>
> Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx>
> ---
> tools/testing/selftests/resctrl/cmt_test.c | 23 ++++++++++---
> tools/testing/selftests/resctrl/mba_test.c | 2 +-
> tools/testing/selftests/resctrl/mbm_test.c | 2 +-
> tools/testing/selftests/resctrl/resctrl.h | 16 ++++++---
> .../testing/selftests/resctrl/resctrl_tests.c | 33 ++++++++-----------
> tools/testing/selftests/resctrl/resctrl_val.c | 10 ++++--
> 6 files changed, 54 insertions(+), 32 deletions(-)
>
> diff --git a/tools/testing/selftests/resctrl/cmt_test.c b/tools/testing/selftests/resctrl/cmt_test.c
> index 9d8e38e995ef..a40e12c3b1a7 100644
> --- a/tools/testing/selftests/resctrl/cmt_test.c
> +++ b/tools/testing/selftests/resctrl/cmt_test.c
> @@ -68,14 +68,16 @@ void cmt_test_cleanup(void)
> remove(RESULT_FILE_NAME);
> }
>
> -int cmt_resctrl_val(int cpu_no, int n, char **benchmark_cmd)
> +int cmt_resctrl_val(int cpu_no, int n, const char * const *benchmark_cmd)
> {
> + const char *cmd[BENCHMARK_ARGS];
> unsigned long cache_size = 0;
> unsigned long long_mask;
> + char *span_str = NULL;
> char cbm_mask[256];
> int count_of_bits;
> size_t span;
> - int ret;
> + int ret, i;
>
> if (!validate_resctrl_feature_request(CMT_STR))
> return -1;
> @@ -111,12 +113,22 @@ int cmt_resctrl_val(int cpu_no, int n, char **benchmark_cmd)
> };
>
> span = cache_size * n / count_of_bits;
> - if (strcmp(benchmark_cmd[0], "fill_buf") == 0)
> - sprintf(benchmark_cmd[1], "%zu", span);
> + /* Duplicate the command to be able to replace span in it */
> + for (i = 0; benchmark_cmd[i]; i++)
> + cmd[i] = benchmark_cmd[i];
> + cmd[i] = NULL;
> +
> + if (strcmp(cmd[0], "fill_buf") == 0) {
> + span_str = malloc(SIZE_MAX_DECIMAL_SIZE);
> + if (!span_str)
> + return -1;
> + snprintf(span_str, SIZE_MAX_DECIMAL_SIZE, "%zu", span);
Have you considered asprintf()?
> + cmd[1] = span_str;
> + }
It looks to me that array only needs to be duplicated if the
default benchmark is used?
>
> remove(RESULT_FILE_NAME);
>
> - ret = resctrl_val(benchmark_cmd, ¶m);
> + ret = resctrl_val(cmd, ¶m);
> if (ret)
> goto out;
>
...
> diff --git a/tools/testing/selftests/resctrl/resctrl.h b/tools/testing/selftests/resctrl/resctrl.h
> index bcd0d2060f81..ddb1e83a3a64 100644
> --- a/tools/testing/selftests/resctrl/resctrl.h
> +++ b/tools/testing/selftests/resctrl/resctrl.h
> @@ -6,6 +6,7 @@
> #include <math.h>
> #include <errno.h>
> #include <sched.h>
> +#include <stdint.h>
> #include <stdlib.h>
> #include <unistd.h>
> #include <string.h>
> @@ -38,7 +39,14 @@
>
> #define END_OF_TESTS 1
>
> +#define BENCHMARK_ARGS 64
> +
> +/* Approximate %zu max length */
> +#define SIZE_MAX_DECIMAL_SIZE (sizeof(SIZE_MAX) * 8 / 3 + 2)
> +
> +/* Define default span both as integer and string, these should match */
> #define DEFAULT_SPAN (250 * MB)
> +#define DEFAULT_SPAN_STR "262144000"
I think above hardcoding can be eliminated by using asprintf()? This
does allocate memory though so I would like to understand why one
goal is to not dynamically allocate memory.
>
> #define PARENT_EXIT(err_msg) \
> do { \
Reinette
