Re: [bisected] pty performance problem

From: Ingo Molnar
Date: Mon Nov 23 2009 - 06:49:02 EST



* Alan Cox <alan@xxxxxxxxxxxxxxxxxxx> wrote:

> > diff --git a/drivers/char/tty_buffer.c b/drivers/char/tty_buffer.c
> > index 66fa4e1..92a0864 100644
> > --- a/drivers/char/tty_buffer.c
> > +++ b/drivers/char/tty_buffer.c
> > @@ -495,7 +495,7 @@ void tty_flip_buffer_push(struct tty_struct *tty)
> > if (tty->low_latency)
> > flush_to_ldisc(&tty->buf.work.work);
> > else
> > - schedule_delayed_work(&tty->buf.work, 1);
> > + schedule_delayed_work(&tty->buf.work, 0);
> > }
> > EXPORT_SYMBOL(tty_flip_buffer_push);
>
> Another possibility is to do
>
> if (tty->low_latency)
> schedule_delayed_work(&tty->buf.work, 0);
> else
> schedule_delayed_work(&tty->buf.work, 1);

Flaggery for low latency is kind of lame though - especially if it
defaults to off in most drivers as you say.

Ingo
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