diff options
| author | Shrikanth Hegde <sshegde@linux.ibm.com> | 2025-03-06 10:59:54 +0530 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2025-03-06 10:21:31 +0100 |
| commit | b1536481c81fb604074da799e4f2d2038a1663f7 (patch) | |
| tree | c42c590abcb5eed4062e028738a97d17e94f876d /Documentation/scheduler | |
| parent | 14672f059d83f591afb2ee1fff56858efe055e5a (diff) | |
sched/rt: Update limit of sched_rt sysctl in documentation
By default fair_server dl_server allocates 5% of the bandwidth to the root
domain. Due to this writing any value less than 5% fails due to -EBUSY:
$ cat /proc/sys/kernel/sched_rt_period_us
1000000
$ echo 49999 > /proc/sys/kernel/sched_rt_runtime_us
-bash: echo: write error: Device or resource busy
$ echo 50000 > /proc/sys/kernel/sched_rt_runtime_us
$
Since the sched_rt_runtime_us allows -1 as the minimum, put this
restriction in the documentation.
One should check average of runtime/period in
/sys/kernel/debug/sched/fair_server/cpuX/* for exact value.
Signed-off-by: Shrikanth Hegde <sshegde@linux.ibm.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Juri Lelli <juri.lelli@redhat.com>
Link: https://lore.kernel.org/r/20250306052954.452005-3-sshegde@linux.ibm.com
Diffstat (limited to 'Documentation/scheduler')
| -rw-r--r-- | Documentation/scheduler/sched-rt-group.rst | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/Documentation/scheduler/sched-rt-group.rst b/Documentation/scheduler/sched-rt-group.rst index 80b05a3009ea..ab464335d320 100644 --- a/Documentation/scheduler/sched-rt-group.rst +++ b/Documentation/scheduler/sched-rt-group.rst @@ -102,6 +102,9 @@ The system wide settings are configured under the /proc virtual file system: * sched_rt_period_us takes values from 1 to INT_MAX. * sched_rt_runtime_us takes values from -1 to sched_rt_period_us. * A run time of -1 specifies runtime == period, ie. no limit. + * sched_rt_runtime_us/sched_rt_period_us > 0.05 inorder to preserve + bandwidth for fair dl_server. For accurate value check average of + runtime/period in /sys/kernel/debug/sched/fair_server/cpuX/ 2.2 Default behaviour |