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>
---
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 | 8 +++++++-
tools/testing/selftests/resctrl/resctrl_val.c | 11 +----------
4 files changed, 13 insertions(+), 15 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..bee4123a5a9b 100644
--- a/tools/testing/selftests/resctrl/resctrl_tests.c
+++ b/tools/testing/selftests/resctrl/resctrl_tests.c
@@ -266,7 +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";
+ /*
+ * 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;
uparams.benchmark_cmd[5] = NULL;
}
diff --git a/tools/testing/selftests/resctrl/resctrl_val.c b/tools/testing/selftests/resctrl/resctrl_val.c
index e88d5ca30517..5331354aaf64 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 */
--
2.46.0
On Thu, 12 Sep 2024, Reinette Chatre wrote:
> 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>
> ---
> 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 | 8 +++++++-
> tools/testing/selftests/resctrl/resctrl_val.c | 11 +----------
> 4 files changed, 13 insertions(+), 15 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..bee4123a5a9b 100644
> --- a/tools/testing/selftests/resctrl/resctrl_tests.c
> +++ b/tools/testing/selftests/resctrl/resctrl_tests.c
> @@ -266,7 +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";
> + /*
> + * 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;
> uparams.benchmark_cmd[5] = NULL;
Why is the [5] assignment kept around? Is something depending on this
double NULL termination? This patch removed the access to [4] so I
don't see anything beyong [3] accessed explicitly.
--
i.
> }
>
> diff --git a/tools/testing/selftests/resctrl/resctrl_val.c b/tools/testing/selftests/resctrl/resctrl_val.c
> index e88d5ca30517..5331354aaf64 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 */
>
Hi Ilpo,
On 9/30/24 6:49 AM, Ilpo Järvinen wrote:
> On Thu, 12 Sep 2024, Reinette Chatre wrote:
>
>> 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>
>> ---
>> 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 | 8 +++++++-
>> tools/testing/selftests/resctrl/resctrl_val.c | 11 +----------
>> 4 files changed, 13 insertions(+), 15 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..bee4123a5a9b 100644
>> --- a/tools/testing/selftests/resctrl/resctrl_tests.c
>> +++ b/tools/testing/selftests/resctrl/resctrl_tests.c
>> @@ -266,7 +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";
>> + /*
>> + * 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;
>> uparams.benchmark_cmd[5] = NULL;
>
> Why is the [5] assignment kept around? Is something depending on this
> double NULL termination? This patch removed the access to [4] so I
> don't see anything beyong [3] accessed explicitly.
>
In this case this was kept to reduce changes in preparatory work since this will
all be replaced later with the more robust parameter handling. I'll remove
the [5] assignment.
Thank you.
Reinette
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