On Wed, Jun 1, 2011 at 7:49 AM, Nick Copeland <nickycopeland(a)hotmail.com> wrote:
I might get flamed for this however GUI should not
really be run with rt
priority,
anyone who would do such a thing is a fool, indeed.
that is an honour for the DSP engines. There are some
reasonable arguments
however for leaning on the scheduler with renice for the user interfaces to
give
them a bit of a bias over other system operations.
what are those arguments? keep in mind that the algorithms inherent in
SCHED_OTHER are targetting console-driven applications that do varying
balances of disk i/o, computation and user input/output. they really
don't address the situation of an app that needs to redraw with a
relatively fixed interval on screen, nor do they provide any actual
scheduling guarantees, which means that any disk i/o issues cannot be
solved with nice - you still have to plan for and deal with the worst
case scenario (which is why ardour's default disk i/o buffers are
*FIVE SECONDS* long (we really have seen delays of this length when
reading from disk!). nice becomes even less relevant in an era of
separate i/o scheduling algorithms that are not designed to pay much
(sometimes no) attention to nice values.