Messages in this thread | | | Date | Mon, 27 Feb 2023 09:24:16 +0700 | From | Bagas Sanjaya <> | Subject | Re: [RFC PATCH v1 1/2] Documentation: btrfs: Document wq_cpu_set mount option |
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On Sun, Feb 26, 2023 at 11:26:38PM +0700, Ammar Faizi wrote: > +wq_cpu_set=<cpu_set> > + (since: 6.5, default: all online CPUs)
Why will the knob be introduced in 6.5 instead?
> + > + Btrfs workqueues can slow sensitive user tasks down because they can use any > + online CPU to perform heavy workloads on an SMP system. This option is used to > + isolate the Btrfs workqueues to a set of CPUs. It is helpful to avoid > + sensitive user tasks being preempted by Btrfs heavy workqueues. > + > + The *cpu_set* is a dot-separated list of decimal numbers and ranges. The > + numbers are CPU numbers, the ranges are inclusive. For example:
"*cpu_set* is a dot-separated list of CPU numbers. Both individual number and range (inclusive) can be listed".
> + > + - *wq_cpu_set=0.3-7* will use CPUs 0, 3, 4, 5, 6 and 7. > + > + - *wq_cpu_set=0.4.1.5* will use CPUs 0, 1, 4 and 5. > + > + This option is similar to the taskset bitmask except that the comma separator > + is replaced with a dot. The reason for this is that the mount option parser > + uses commas to separate mount options.
"... replaced by dots, since commas has already been used as mount options separator".
> + If *wq_cpu_set* option is specificed and the *thread_pool* option is also > + specified, the thread pool size will be set to the value of *thread_pool* > + option.
"If both options are set ..."
Thanks.
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