diff options
| author | Frederic Weisbecker <frederic@kernel.org> | 2026-05-08 15:16:45 +0200 |
|---|---|---|
| committer | Thomas Gleixner <tglx@kernel.org> | 2026-06-02 21:27:26 +0200 |
| commit | 3b45b4f188f3a0ebd16ab71efd2ffcc7a16ad861 (patch) | |
| tree | b51b82e3b7602d9c72f1f69e2810fb2ff3e05de5 /kernel/sched | |
| parent | 127b2eb44f36d5d7059f1af425b5800cb27440f9 (diff) | |
sched/cputime: Provide get_cpu_[idle|iowait]_time_us() off-case
The last reason why get_cpu_idle/iowait_time_us() may return -1 now is if
the config doesn't support nohz.
The ad-hoc replacement solution by cpufreq is to compute jiffies minus the
whole busy cputime. Although the intention should provide a coherent low
resolution estimation of the idle and iowait time, the implementation is
buggy because jiffies don't start at 0.
Just provide instead a real get_cpu_[idle|iowait]_time_us() offcase.
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Tested-by: Shrikanth Hegde <sshegde@linux.ibm.com>
Link: https://patch.msgid.link/20260508131647.43868-14-frederic@kernel.org
Diffstat (limited to 'kernel/sched')
| -rw-r--r-- | kernel/sched/cputime.c | 12 |
1 files changed, 9 insertions, 3 deletions
diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c index c91fd67f93ea..335d2c127763 100644 --- a/kernel/sched/cputime.c +++ b/kernel/sched/cputime.c @@ -522,6 +522,13 @@ u64 kcpustat_field_iowait(int cpu) nr_iowait_cpu(cpu), ktime_get()); } EXPORT_SYMBOL_GPL(kcpustat_field_iowait); +#else +static u64 kcpustat_field_dyntick(int cpu, enum cpu_usage_stat idx, + bool compute_delta, ktime_t now) +{ + return kcpustat_cpu(cpu).cpustat[idx]; +} +#endif /* CONFIG_NO_HZ_COMMON */ static u64 get_cpu_sleep_time_us(int cpu, enum cpu_usage_stat idx, bool compute_delta, u64 *last_update_time) @@ -557,7 +564,7 @@ static u64 get_cpu_sleep_time_us(int cpu, enum cpu_usage_stat idx, * This time is measured via accounting rather than sampling, * and is as accurate as ktime_get() is. * - * Return: -1 if generic vtime is enabled, else total idle time of the @cpu + * Return: total idle time of the @cpu */ u64 get_cpu_idle_time_us(int cpu, u64 *last_update_time) { @@ -581,7 +588,7 @@ EXPORT_SYMBOL_GPL(get_cpu_idle_time_us); * This time is measured via accounting rather than sampling, * and is as accurate as ktime_get() is. * - * Return: -1 if generic vtime is enabled, else total iowait time of @cpu + * Return: total iowait time of @cpu */ u64 get_cpu_iowait_time_us(int cpu, u64 *last_update_time) { @@ -589,7 +596,6 @@ u64 get_cpu_iowait_time_us(int cpu, u64 *last_update_time) nr_iowait_cpu(cpu), last_update_time); } EXPORT_SYMBOL_GPL(get_cpu_iowait_time_us); -#endif /* CONFIG_NO_HZ_COMMON */ /* * Use precise platform statistics if available: |