When should I not use CLONE_IO?

[Steven Stewart-Gallus <sstewartgallus00@mylangara.bc.ca>]

Hello,

Currently GLibc does not use CLONE_IO and does not expose a way to use CLONE_IO
(for threads which are where it'd be most useful I assume). The documentation is
unclear though and leaves me in the dark about a lot. For example, I don't see
why GLibc shouldn't use CLONE_IO with every thread by default. Also, it seems to
me that if threads share I/O contexts they should also have to share I/O
schedulers right? Does this mean that if threads share I/O contexts with
CLONE_IO that sched_setscheduler either severs the I/O context sharing or sets
the same scheduler for both of them? Even if the threads sharing the same I/O
context must use the same scheduler can they have different priorities?

Thank you,
Steven Stewart-Gallus