selftests/resctrl: Remove "once" parameter required to be false

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>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

diff --git a/tools/testing/selftests/resctrl/fill_buf.c b/tools/testing/selftests/resctrl/fill_buf.c
index 34e5df721430ee101781fbefc445d680775bf2fc..854f0108d8e62c6a25b900445b03a57e09cdc4a5 100644 (file)
--- 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 2dda560845880e3c5a19101382856a3b27c9c16e..51f5f4b25e0662285ce7536c875475d5e7d18d7a 100644 (file)
--- 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 ecbb7605a981526f96ee62d946ada8d67e72abe2..e7878077883f0bebb7511e00a7473de3d71d79a6 100644 (file)
--- a/tools/testing/selftests/resctrl/resctrl_tests.c
+++ b/tools/testing/selftests/resctrl/resctrl_tests.c
@@ -266,8 +266,13 @@ last_arg:
                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 c9dd70ce3ea87c7c089a4bc19d194f674c0468bc..b0f3c594c4da4721ee63772aee38c9f21d51337a 100644 (file)
--- 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 */