The CMT, MBM, and MBA tests rely on a benchmark that runs while the test makes changes to needed configuration (for example memory bandwidth allocation) and takes needed measurements. By default the "fill_buf" benchmark is used and by default (via its "once = false" setting) "fill_buf" is configured to run until terminated after the test completes.
An unintended consequence of enabling the user to override the benchmark also enables the user to change parameters to the "fill_buf" benchmark. This enables the user to set "fill_buf" to only cycle through the buffer once (by setting "once = true") and thus breaking the CMT, MBA, and MBM tests that expect workload/interference to be reflected by their measurements.
Prevent user space from changing the "once" parameter and ensure that it is always false for the CMT, MBA, and MBM tests.
Suggested-by: Ilpo Järvinen ilpo.jarvinen@linux.intel.com Signed-off-by: Reinette Chatre reinette.chatre@intel.com Reviewed-by: Ilpo Järvinen ilpo.jarvinen@linux.intel.com --- Changes since V3: - Add Ilpo's Reviewed-by tag.
Changes since V2: - Remove unnecessary assignment to benchmark_cmd[5]. (Ilpo)
Changes since V1: - New patch --- tools/testing/selftests/resctrl/fill_buf.c | 7 ++++--- tools/testing/selftests/resctrl/resctrl.h | 2 +- tools/testing/selftests/resctrl/resctrl_tests.c | 9 +++++++-- tools/testing/selftests/resctrl/resctrl_val.c | 11 +---------- 4 files changed, 13 insertions(+), 16 deletions(-)
diff --git a/tools/testing/selftests/resctrl/fill_buf.c b/tools/testing/selftests/resctrl/fill_buf.c index 34e5df721430..854f0108d8e6 100644 --- a/tools/testing/selftests/resctrl/fill_buf.c +++ b/tools/testing/selftests/resctrl/fill_buf.c @@ -151,7 +151,7 @@ unsigned char *alloc_buffer(size_t buf_size, int memflush) return buf; }
-int run_fill_buf(size_t buf_size, int memflush, int op, bool once) +int run_fill_buf(size_t buf_size, int memflush, int op) { unsigned char *buf;
@@ -160,9 +160,10 @@ int run_fill_buf(size_t buf_size, int memflush, int op, bool once) return -1;
if (op == 0) - fill_cache_read(buf, buf_size, once); + fill_cache_read(buf, buf_size, false); else - fill_cache_write(buf, buf_size, once); + fill_cache_write(buf, buf_size, false); + free(buf);
return 0; diff --git a/tools/testing/selftests/resctrl/resctrl.h b/tools/testing/selftests/resctrl/resctrl.h index 2dda56084588..51f5f4b25e06 100644 --- a/tools/testing/selftests/resctrl/resctrl.h +++ b/tools/testing/selftests/resctrl/resctrl.h @@ -142,7 +142,7 @@ int perf_event_open(struct perf_event_attr *hw_event, pid_t pid, int cpu, unsigned char *alloc_buffer(size_t buf_size, int memflush); void mem_flush(unsigned char *buf, size_t buf_size); void fill_cache_read(unsigned char *buf, size_t buf_size, bool once); -int run_fill_buf(size_t buf_size, int memflush, int op, bool once); +int run_fill_buf(size_t buf_size, int memflush, int op); int initialize_mem_bw_imc(void); int measure_mem_bw(const struct user_params *uparams, struct resctrl_val_param *param, pid_t bm_pid, diff --git a/tools/testing/selftests/resctrl/resctrl_tests.c b/tools/testing/selftests/resctrl/resctrl_tests.c index ecbb7605a981..e7878077883f 100644 --- a/tools/testing/selftests/resctrl/resctrl_tests.c +++ b/tools/testing/selftests/resctrl/resctrl_tests.c @@ -266,8 +266,13 @@ int main(int argc, char **argv) uparams.benchmark_cmd[1] = span_str; uparams.benchmark_cmd[2] = "1"; uparams.benchmark_cmd[3] = "0"; - uparams.benchmark_cmd[4] = "false"; - uparams.benchmark_cmd[5] = NULL; + /* + * Fourth parameter was previously used to indicate + * how long "fill_buf" should run for, with "false" + * ("fill_buf" will keep running until terminated) + * the only option that works. + */ + uparams.benchmark_cmd[4] = NULL; }
ksft_set_plan(tests); diff --git a/tools/testing/selftests/resctrl/resctrl_val.c b/tools/testing/selftests/resctrl/resctrl_val.c index c9dd70ce3ea8..b0f3c594c4da 100644 --- a/tools/testing/selftests/resctrl/resctrl_val.c +++ b/tools/testing/selftests/resctrl/resctrl_val.c @@ -625,7 +625,6 @@ static void run_benchmark(int signum, siginfo_t *info, void *ucontext) int operation, ret, memflush; char **benchmark_cmd; size_t span; - bool once; FILE *fp;
benchmark_cmd = info->si_ptr; @@ -645,16 +644,8 @@ static void run_benchmark(int signum, siginfo_t *info, void *ucontext) span = strtoul(benchmark_cmd[1], NULL, 10); memflush = atoi(benchmark_cmd[2]); operation = atoi(benchmark_cmd[3]); - if (!strcmp(benchmark_cmd[4], "true")) { - once = true; - } else if (!strcmp(benchmark_cmd[4], "false")) { - once = false; - } else { - ksft_print_msg("Invalid once parameter\n"); - parent_exit(ppid); - }
- if (run_fill_buf(span, memflush, operation, once)) + if (run_fill_buf(span, memflush, operation)) fprintf(stderr, "Error in running fill buffer\n"); } else { /* Execute specified benchmark */