Messages in this thread Patch in this message | | | Subject | Re: [bisected] pty performance problem | From | Mike Galbraith <> | Date | Mon, 23 Nov 2009 06:00:31 +0100 |
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On Sun, 2009-11-22 at 12:23 +0000, Alan Cox wrote: > On Sun, 22 Nov 2009 07:39:26 +0100 > Ingo Molnar <mingo@elte.hu> wrote: > > > > > (Cc:-ed Alan and Linus - mail repeated below. eot.) > > I saw it and replied already. The kernel now queues the work for the pty > as it does normal tty devices. If the CPU load is that low and nothing > else is happening it makes me wonder what the scheduler thinks it is > doing ?
Hm. Looks to me like it's doing what it was told to do.
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); Telling it to execute now made test proggy happy.. and likely broke tons of things that need a delay there. So, what's wrong with delaying, when that's what the customer asked for? /me must be missing something. It could know that no delay is needed? -Mike
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