From e176058f0de53c2346734e5254835e0045364001 Mon Sep 17 00:00:00 2001 From: Peter Hurley Date: Sat, 17 Oct 2015 16:36:23 -0400 Subject: tty: Abstract tty buffer work Introduce API functions to restart and cancel tty buffer work, rather than manipulate buffer work directly. Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman --- drivers/tty/tty_buffer.c | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'drivers/tty/tty_buffer.c') diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c index a660ab181cca..7cc16db37e0e 100644 --- a/drivers/tty/tty_buffer.c +++ b/drivers/tty/tty_buffer.c @@ -587,3 +587,13 @@ void tty_buffer_set_lock_subclass(struct tty_port *port) { lockdep_set_subclass(&port->buf.lock, TTY_LOCK_SLAVE); } + +bool tty_buffer_restart_work(struct tty_port *port) +{ + return queue_work(system_unbound_wq, &port->buf.work); +} + +bool tty_buffer_cancel_work(struct tty_port *port) +{ + return cancel_work_sync(&port->buf.work); +} -- cgit v1.2.3 From e052c6d15c61cc4caff2f06cbca72b183da9f15e Mon Sep 17 00:00:00 2001 From: Peter Hurley Date: Sat, 17 Oct 2015 16:36:24 -0400 Subject: tty: Use unbound workqueue for all input workers The commonly accepted wisdom that scheduling work on the same cpu that handled interrupt i/o benefits from cache-locality is only true if the cpu is idle (since bound kworkers are often the highest vruntime and thus the lowest priority). Measurements of scheduling via the unbound queue show lowered worst-case latency responses of up to 5x over bound workqueue, without increase in average latency or throughput. pty i/o test measurements show >3x (!) reduced total running time; tests previously taking ~8s now complete in <2.5s. Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman --- drivers/tty/tty_buffer.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/tty/tty_buffer.c') diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c index 7cc16db37e0e..9a479e61791a 100644 --- a/drivers/tty/tty_buffer.c +++ b/drivers/tty/tty_buffer.c @@ -403,7 +403,7 @@ void tty_schedule_flip(struct tty_port *port) * flush_to_ldisc() sees buffer data. */ smp_store_release(&buf->tail->commit, buf->tail->used); - schedule_work(&buf->work); + queue_work(system_unbound_wq, &buf->work); } EXPORT_SYMBOL(tty_schedule_flip); -- cgit v1.2.3