On 12/17/18, Jiri Kosina <jikos@xxxxxxxxxx> wrote: > On Sun, 16 Dec 2018, Jiri Kosina wrote: > >> They have that choice. SMT can be disabled on kernel cmdline, and in >> many cases also in BIOS. > > And if your worry is about the code size (that the kernel scheduler always > has the SMT-aware bits in it), I guess making it conditional should be > backed by real usecase. > > The current situation is backed mostly by the fact that there is no known > usecase that'd want it disabled, everybody we are aware of out there is > enabling it. > I have already pointed out that some distros are not enabling it. Your argument is like saying "All of the distros have enabled CONFIG_SOUND, so let us always force it enabled". Yet, there are situations where they don't want sound. And perhaps, in an embedded application, they might want to par the kernel down to the essentials, for maximum simplicity and security, keeping SMP if the kernel has multiple cores, but not needing SCHED_SMT. I can see an engineer wanting that choice. Regards, Barry Kauler
