On Thu, 8 Sep 2016 18:33:25 +0300 Noam Camus <[email protected]> wrote:
> Today there are platforms with many CPUs (up to 4K). > Trying to boot only part of the CPUs may result in too long string. > > For example lets take NPS platform that is part of arch/arc. > This platform have SMP system with 256 cores each with > 16 HW threads (SMT machine) where HW thread appears as CPU to the kernel. > In this example there is total of 4K CPUs. > When one tries to boot only part of the HW threads from each core the > string representing the map may be long... > For example if for sake of performance we decided to boot only first half > of HW threads of each core the map will look like: > 0-7,16-23,32-39,...,4080-4087 > > This patch introduce new syntax to accommodate with such use case. > I added an optional postfix to a range of CPUs which will choose > according to given modulo the desired range of reminders i.e.: > <cpus range>:sed_size/group_size > > For example, above map can be described in new syntax like this: > 0-4095:8/16 There should be some updates to the user-facing documentation, please. Documentation/kernel-parameters.txt, mainly. Which boot parameters does this affect? For example, I think it accidentally alters isolcpus=? It would be useful to see the patch which wires this up (to arch/arc?).
