diff options
| author | Josh Don <joshdon@google.com> | 2021-08-27 09:54:38 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-11-17 11:03:48 +0100 |
| commit | aa171d3e8556655bb4036e347510b60574b5740f (patch) | |
| tree | 7c360456dd477954afcfa616abd3c0eefdf8baf4 /include/linux/kernel_stat.h | |
| parent | 09bdbbc622e33d7bfb3475b695254e562cfdba48 (diff) | |
fs/proc/uptime.c: Fix idle time reporting in /proc/uptime
[ Upstream commit a130e8fbc7de796eb6e680724d87f4737a26d0ac ]
/proc/uptime reports idle time by reading the CPUTIME_IDLE field from
the per-cpu kcpustats. However, on NO_HZ systems, idle time is not
continually updated on idle cpus, leading this value to appear
incorrectly small.
/proc/stat performs an accounting update when reading idle time; we
can use the same approach for uptime.
With this patch, /proc/stat and /proc/uptime now agree on idle time.
Additionally, the following shows idle time tick up consistently on an
idle machine:
(while true; do cat /proc/uptime; sleep 1; done) | awk '{print $2-prev; prev=$2}'
Reported-by: Luigi Rizzo <lrizzo@google.com>
Signed-off-by: Josh Don <joshdon@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://lkml.kernel.org/r/20210827165438.3280779-1-joshdon@google.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'include/linux/kernel_stat.h')
| -rw-r--r-- | include/linux/kernel_stat.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/kernel_stat.h b/include/linux/kernel_stat.h index 44ae1a7eb9e3..69ae6b278464 100644 --- a/include/linux/kernel_stat.h +++ b/include/linux/kernel_stat.h @@ -102,6 +102,7 @@ extern void account_system_index_time(struct task_struct *, u64, enum cpu_usage_stat); extern void account_steal_time(u64); extern void account_idle_time(u64); +extern u64 get_idle_time(struct kernel_cpustat *kcs, int cpu); #ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE static inline void account_process_tick(struct task_struct *tsk, int user) |