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selftests/cgroup: Adjust cpu test duration based on HZ

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For lower HZ values a quota of 1000us is much lower than the amount
of microseconds per tick which makes the tests test_cpucg_max and
test_cpugc_max_nested fail. Increase the test duration to accommodate
for lower HZ values.

Link: https://lore.kernel.org/lkml/20260625203307.1114538-1-joest@redhat.com/
Signed-off-by: Joe Simmons-Talbott <joest@redhat.com>
Acked-by: Michal Koutný <mkoutny@suse.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
This commit is contained in:
Joe Simmons-Talbott
2026-06-26 16:29:22 -04:00
committed by Tejun Heo
parent da43ea2139
commit a2703c2980
2 changed files with 38 additions and 6 deletions
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1
tools/testing/selftests/cgroup/lib/include/cgroup_util.h
View File

@@ -8,6 +8,7 @@
#define MB(x) (x << 20)
#define NSEC_PER_USEC 1000L
#define USEC_PER_SEC 1000000L
#define NSEC_PER_SEC 1000000000L

43
tools/testing/selftests/cgroup/test_cpu.c
View File

@@ -639,6 +639,31 @@ test_cpucg_nested_weight_underprovisioned(const char *root)
return run_cpucg_nested_weight_test(root, false);
}
/*
* Best effort attempt to get the kernel's HZ value from the config.
* Return the HZ value if found otherwise return 1000 (the default) to
* indicate failure.
*/
static long
get_config_hz(void)
{
long hz = 1000;
FILE *f;
char cmd[256] = "zcat /proc/config.gz 2>/dev/null | grep '^CONFIG_HZ='";
f = popen(cmd, "r");
if (!f)
return hz;
if (fscanf(f, "CONFIG_HZ=%ld", &hz) == EOF)
goto out;
out:
pclose(f);
return hz;
}
/*
* This test creates a cgroup with some maximum value within a period, and
* verifies that a process in the cgroup is not overscheduled.
@@ -646,15 +671,18 @@ test_cpucg_nested_weight_underprovisioned(const char *root)
static int test_cpucg_max(const char *root)
{
int ret = KSFT_FAIL;
long hz = get_config_hz();
long quota_usec = 1000;
long default_period_usec = 100000; /* cpu.max's default period */
long duration_seconds = 1;
long duration_usec = duration_seconds * USEC_PER_SEC;
long duration_usec;
long usage_usec, n_periods, remainder_usec, expected_usage_usec;
char *cpucg;
char quota_buf[32];
duration_usec = duration_seconds * USEC_PER_SEC * 1000 / hz;
snprintf(quota_buf, sizeof(quota_buf), "%ld", quota_usec);
cpucg = cg_name(root, "cpucg_test");
@@ -670,8 +698,8 @@ static int test_cpucg_max(const char *root)
struct cpu_hog_func_param param = {
.nprocs = 1,
.ts = {
.tv_sec = duration_seconds,
.tv_nsec = 0,
.tv_sec = duration_usec / USEC_PER_SEC,
.tv_nsec = duration_usec % USEC_PER_SEC * NSEC_PER_USEC,
},
.clock_type = CPU_HOG_CLOCK_WALL,
};
@@ -710,15 +738,18 @@ static int test_cpucg_max(const char *root)
static int test_cpucg_max_nested(const char *root)
{
int ret = KSFT_FAIL;
long hz = get_config_hz();
long quota_usec = 1000;
long default_period_usec = 100000; /* cpu.max's default period */
long duration_seconds = 1;
long duration_usec = duration_seconds * USEC_PER_SEC;
long duration_usec;
long usage_usec, n_periods, remainder_usec, expected_usage_usec;
char *parent, *child;
char quota_buf[32];
duration_usec = duration_seconds * USEC_PER_SEC * 1000 / hz;
snprintf(quota_buf, sizeof(quota_buf), "%ld", quota_usec);
parent = cg_name(root, "cpucg_parent");
@@ -741,8 +772,8 @@ static int test_cpucg_max_nested(const char *root)
struct cpu_hog_func_param param = {
.nprocs = 1,
.ts = {
.tv_sec = duration_seconds,
.tv_nsec = 0,
.tv_sec = duration_usec / USEC_PER_SEC,
.tv_nsec = duration_usec % USEC_PER_SEC * NSEC_PER_USEC,
},
.clock_type = CPU_HOG_CLOCK_WALL,
};