* Frederic Weisbecker <frede...@kernel.org> wrote:
> Update the documentation to reflect the 1Hz tick offload changes.
>
> Signed-off-by: Frederic Weisbecker <frede...@kernel.org>
> Cc: Chris Metcalf <cmetc...@mellanox.com>
> Cc: Christoph Lameter <c...@linux.com>
> Cc: Luiz Capitulino <lcapitul...@redhat.com>
> Cc: Mike Galbraith <efa...@gmx.de>
> Cc: Paul E. McKenney <paul...@linux.vnet.ibm.com>
> Cc: Peter Zijlstra <pet...@infradead.org>
> Cc: Rik van Riel <r...@redhat.com>
> Cc: Thomas Gleixner <t...@linutronix.de>
> Cc: Wanpeng Li <kernel...@gmail.com>
> Cc: Ingo Molnar <mi...@kernel.org>
> ---
> Documentation/admin-guide/kernel-parameters.txt | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/admin-guide/kernel-parameters.txt
> b/Documentation/admin-guide/kernel-parameters.txt
> index 39ac9d4..c851e41 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -1762,7 +1762,11 @@
> specified in the flag list (default: domain):
>
> nohz
> - Disable the tick when a single task runs.
> + Disable the tick when a single task runs. A residual
> 1Hz
> + tick is offloaded to workqueues that you need to
> affine
> + to housekeeping through the sysfs file
> + /sys/devices/virtual/workqueue/cpumask or using the
> below
> + domain flag.
This is pretty ambiguous and somewhat confusing, I'd suggest something like:
nohz
Disable the tick when a single task runs.
A residual 1Hz tick is offloaded to workqueues, which
you
need to affine to housekeeping through the global
workqueue's affinity configured via the
/sys/devices/virtual/workqueue/cpumask sysfs file, or
by using the 'domain' flag described below.
NOTE: by default the global workqueue runs on all
CPUs,
so to protect individual CPUs the 'cpumask' file has
to
be configured manually after bootup.
Assuming what I wrote is correct - the CPU isolation config space is pretty
confusing all around and should be made a lot more human friendly ...
Thanks,
Ingo
