4045 zfs write throttle & i/o scheduler performance work

[Andriy Gapon]

I wonder if anyone already has a patch for integrating "4045 zfs write throttle
& i/o scheduler performance work" from Illumos to FreeBSD.  Or if anyone is
working on this.

We would like to test this change in our environment as soon as possible.  So I
could start working on it if needed.

BTW, it seems that "3581 spa_zio_taskq[ZIO_TYPE_FREE][ZIO_TASKQ_ISSUE]->tq_lock
is piping hot" was not integrated into FreeBSD despite being committed to
Illumos back in February.  I am not sure if we need the main change from this
commit, but, as it is frequent with Illumos commits, it contains some changes to
definitions of some macros, enums and structs.  So I think it is worth having
that change merged, at least partially.  That would help with merge the future
changing including "4045 zfs write throttle & i/o scheduler performance work".

P.S.
Do we have a FreeBSD ZFS IRC channel?  Should we?
-- 
Andriy Gapon