Commit-ID: b0d40d2b22fe48cfcbbfb137fd198be0a1cd8a85 Gitweb: https://git.kernel.org/tip/b0d40d2b22fe48cfcbbfb137fd198be0a1cd8a85 Author: Frederic Weisbecker <frederic@xxxxxxxxxx> AuthorDate: Tue, 31 Oct 2017 04:18:34 +0100 Committer: Ingo Molnar <mingo@xxxxxxxxxx> CommitDate: Tue, 31 Oct 2017 10:29:39 +0100 sched/isolation: Document isolcpus= boot parameter flags, mark it deprecated Document the latest updates on the isolcpus= boot option. While at it, let's also fix the details about the preferred way to isolate a set of CPUs from the scheduler general domains. Cpusets offer a much better interface to achieve that. Signed-off-by: Frederic Weisbecker <frederic@xxxxxxxxxx> Acked-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Acked-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Chris Metcalf <cmetcalf@xxxxxxxxxxxx> Cc: Christoph Lameter <cl@xxxxxxxxx> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Cc: Luiz Capitulino <lcapitulino@xxxxxxxxxx> Cc: Mike Galbraith <efault@xxxxxx> Cc: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx> Cc: Rik van Riel <riel@xxxxxxxxxx> Cc: Wanpeng Li <kernellwp@xxxxxxxxx> Link: http://lkml.kernel.org/r/1509419914-16179-1-git-send-email-frederic@xxxxxxxxxx [ Clarified the text some more, marked the boot option deprecated. ] Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> --- Documentation/admin-guide/kernel-parameters.txt | 39 ++++++++++++++++--------- 1 file changed, 26 insertions(+), 13 deletions(-) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 6b99c8b..17eb023 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -1727,20 +1727,33 @@ isapnp= [ISAPNP] Format: <RDP>,<reset>,<pci_scan>,<verbosity> - isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler. - The argument is a cpu list, as described above. + isolcpus= [KNL,SMP] Isolate a given set of CPUs from disturbance. + [Deprecated - use cpusets instead] + Format: [flag-list,]<cpu-list> + + Specify one or more CPUs to isolate from disturbances + specified in the flag list (default: domain): + + nohz + Disable the tick when a single task runs. + domain + Isolate from the general SMP balancing and scheduling + algorithms. Note that performing domain isolation this way + is irreversible: it's not possible to bring back a CPU to + the domains once isolated through isolcpus. It's strongly + advised to use cpusets instead to disable scheduler load + balancing through the "cpuset.sched_load_balance" file. + It offers a much more flexible interface where CPUs can + move in and out of an isolated set anytime. + + You can move a process onto or off an "isolated" CPU via + the CPU affinity syscalls or cpuset. + <cpu number> begins at 0 and the maximum value is + "number of CPUs in system - 1". + + The format of <cpu-list> is described above. + - This option can be used to specify one or more CPUs - to isolate from the general SMP balancing and scheduling - algorithms. You can move a process onto or off an - "isolated" CPU via the CPU affinity syscalls or cpuset. - <cpu number> begins at 0 and the maximum value is - "number of CPUs in system - 1". - - This option is the preferred way to isolate CPUs. The - alternative -- manually setting the CPU mask of all - tasks in the system -- can cause problems and - suboptimal load balancer performance. iucv= [HW,NET] -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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