Hello Oleksij, On Thu, 10 Jan 2019 11:12:32 +0100 Oleksij Rempel <o.rem...@pengutronix.de> wrote:
> sched_priority = 1 is enough to dramatically reduce latency > on have system load produced by tasks with default user space prio. > > Signed-off-by: Oleksij Rempel <o.rem...@pengutronix.de> Tested-by: Alexander Sverdlin <alexander.sverd...@gmail.com> > --- > drivers/tty/tty_buffer.c | 12 +++++++++++- > 1 file changed, 11 insertions(+), 1 deletion(-) > > diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c > index 18bd7f48a319..7cf42f6570a0 100644 > --- a/drivers/tty/tty_buffer.c > +++ b/drivers/tty/tty_buffer.c > @@ -13,11 +13,13 @@ > #include <linux/string.h> > #include <linux/slab.h> > #include <linux/sched.h> > +#include <linux/sched/rt.h> > #include <linux/wait.h> > #include <linux/bitops.h> > #include <linux/delay.h> > #include <linux/module.h> > #include <linux/ratelimit.h> > +#include <uapi/linux/sched/types.h> > > > #define MIN_TTYB_SIZE 256 > @@ -567,7 +569,15 @@ bool tty_buffer_queue_work(struct tty_port *port) > > void tty_buffer_init_kthread(void) > { > - kthread_run(kthread_worker_fn, &tty_buffer_worker, "tty"); > + struct sched_param param = { .sched_priority = 1 }; > + struct task_struct *kworker_task; > + > + kworker_task = kthread_run(kthread_worker_fn, &tty_buffer_worker, > "tty"); > + if (IS_ERR(kworker_task)) { > + pr_err("failed to create message pump task\n"); > + return; > + } > + sched_setscheduler(kworker_task, SCHED_FIFO, ¶m); > } > > /** -- Alexander Sverdlin.