[PATCH v2 14/26] selftests/resctrl: Convert perf related globals to locals

Ilpo Järvinen
2023-11-20T11:15:54Z

Perf related variables pea_llc_miss, pe_read, and pe_fd are globals in
cache.c.

Convert them to locals for better scoping and make pea_llc_miss simpler
by renaming it to pea. Make close(pe_fd) handling easier to understand
by doing it inside cat_val().

Make also sizeof()s use safer way to determine the right struct.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
---
tools/testing/selftests/resctrl/cache.c | 72 ++++++++++++++-----------
1 file changed, 40 insertions(+), 32 deletions(-)

diff --git a/tools/testing/selftests/resctrl/cache.c b/tools/testing/selftests/resctrl/cache.c
index 315f30f23371..a69e7151db94 100644
--- a/tools/testing/selftests/resctrl/cache.c
+++ b/tools/testing/selftests/resctrl/cache.c
@@ -10,51 +10,50 @@ struct perf_event_read {
} values[2];
};

-static struct perf_event_attr pea_llc_miss;
-static struct perf_event_read pe_read;
-static int pe_fd;
char llc_occup_path[1024];

-static void perf_event_attr_initialize(__u64 config)
+static void perf_event_attr_initialize(struct perf_event_attr *pea, __u64 config)
{
- memset(&pea_llc_miss, 0, sizeof(struct perf_event_attr));
- pea_llc_miss.type = PERF_TYPE_HARDWARE;
- pea_llc_miss.size = sizeof(struct perf_event_attr);
- pea_llc_miss.read_format = PERF_FORMAT_GROUP;
- pea_llc_miss.exclude_kernel = 1;
- pea_llc_miss.exclude_hv = 1;
- pea_llc_miss.exclude_idle = 1;
- pea_llc_miss.exclude_callchain_kernel = 1;
- pea_llc_miss.inherit = 1;
- pea_llc_miss.exclude_guest = 1;
- pea_llc_miss.disabled = 1;
- pea_llc_miss.config = config;
+ memset(pea, 0, sizeof(*pea));
+ pea->type = PERF_TYPE_HARDWARE;
+ pea->size = sizeof(*pea);
+ pea->read_format = PERF_FORMAT_GROUP;
+ pea->exclude_kernel = 1;
+ pea->exclude_hv = 1;
+ pea->exclude_idle = 1;
+ pea->exclude_callchain_kernel = 1;
+ pea->inherit = 1;
+ pea->exclude_guest = 1;
+ pea->disabled = 1;
+ pea->config = config;
}

/* Start counters to log values */
-static void perf_event_reset_enable(void)
+static void perf_event_reset_enable(int pe_fd)
{
ioctl(pe_fd, PERF_EVENT_IOC_RESET, 0);
ioctl(pe_fd, PERF_EVENT_IOC_ENABLE, 0);
}

-static void perf_event_initialize_read_format(void)
+static void perf_event_initialize_read_format(struct perf_event_read *pe_read)
{
- memset(&pe_read, 0, sizeof(struct perf_event_read));
- pe_read.nr = 1;
+ memset(pe_read, 0, sizeof(*pe_read));
+ pe_read->nr = 1;
}

-static int perf_open(pid_t pid, int cpu_no)
+static int perf_open(struct perf_event_attr *pea, pid_t pid, int cpu_no)
{
- pe_fd = perf_event_open(&pea_llc_miss, pid, cpu_no, -1, PERF_FLAG_FD_CLOEXEC);
+ int pe_fd;
+
+ pe_fd = perf_event_open(pea, pid, cpu_no, -1, PERF_FLAG_FD_CLOEXEC);
if (pe_fd == -1) {
perror("Error opening leader");
return -1;
}

- perf_event_reset_enable();
+ perf_event_reset_enable(pe_fd);

- return 0;
+ return pe_fd;
}

/*
@@ -131,20 +130,21 @@ static int print_results_cache(const char *filename, int bm_pid, __u64 llc_value
*
* Return: =0 on success. <0 on failure.
*/
-static int perf_event_measure(const char *filename, int bm_pid)
+static int perf_event_measure(int pe_fd, struct perf_event_read *pe_read,
+ const char *filename, int bm_pid)
{
int ret;

/* Stop counters after one span to get miss rate */
ioctl(pe_fd, PERF_EVENT_IOC_DISABLE, 0);

- ret = read(pe_fd, &pe_read, sizeof(struct perf_event_read));
+ ret = read(pe_fd, pe_read, sizeof(*pe_read));
if (ret == -1) {
perror("Could not get perf value");
return -1;
}

- return print_results_cache(filename, bm_pid, pe_read.values[0].value);
+ return print_results_cache(filename, bm_pid, pe_read->values[0].value);
}

/*
@@ -182,7 +182,10 @@ int cat_val(struct resctrl_val_param *param, size_t span)
{
int memflush = 1, operation = 0, ret = 0;
char *resctrl_val = param->resctrl_val;
+ struct perf_event_read pe_read;
+ struct perf_event_attr pea;
pid_t bm_pid;
+ int pe_fd;

if (strcmp(param->filename, "") == 0)
sprintf(param->filename, "stdio");
@@ -200,8 +203,8 @@ int cat_val(struct resctrl_val_param *param, size_t span)
if (ret)
return ret;

- perf_event_attr_initialize(PERF_COUNT_HW_CACHE_MISSES);
- perf_event_initialize_read_format();
+ perf_event_attr_initialize(&pea, PERF_COUNT_HW_CACHE_MISSES);
+ perf_event_initialize_read_format(&pe_read);

/* Test runs until the callback setup() tells the test to stop. */
while (1) {
@@ -212,9 +215,12 @@ int cat_val(struct resctrl_val_param *param, size_t span)
}
if (ret < 0)
break;
- ret = perf_open(bm_pid, param->cpu_no);
- if (ret)
+
+ pe_fd = perf_open(&pea, bm_pid, param->cpu_no);
+ if (pe_fd < 0) {
+ ret = -1;
break;
+ }

if (run_fill_buf(span, memflush, operation, true)) {
fprintf(stderr, "Error-running fill buffer\n");
@@ -223,9 +229,11 @@ int cat_val(struct resctrl_val_param *param, size_t span)
}

sleep(1);
- ret = perf_event_measure(param->filename, bm_pid);
+ ret = perf_event_measure(pe_fd, &pe_read, param->filename, bm_pid);
if (ret)
goto pe_close;
+
+ close(pe_fd);
}

return ret;
--
2.30.2