Re: Slow pty's (was Re: libdivecomputer interfaces?)

From: Mike Galbraith
Date: Thu Jun 17 2010 - 10:14:57 EST


On Thu, 2010-06-17 at 15:24 +0200, Peter Zijlstra wrote:

> Humm,. the code around there suggests something like the below, but I
> must admit its been a while since I really read all that nohz stuff,
> Thomas, any preferences?

Mine works. Yours fits and works. -+ vs ----+, you win :)


> ---
> kernel/time/tick-sched.c | 5 +----
> 1 files changed, 1 insertions(+), 4 deletions(-)
>
> diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
> index 5f171f0..e0707ea 100644
> --- a/kernel/time/tick-sched.c
> +++ b/kernel/time/tick-sched.c
> @@ -315,9 +315,6 @@ void tick_nohz_stop_sched_tick(int inidle)
> goto end;
> }
>
> - if (nohz_ratelimit(cpu))
> - goto end;
> -
> ts->idle_calls++;
> /* Read jiffies and the time when jiffies were updated last */
> do {
> @@ -328,7 +325,7 @@ void tick_nohz_stop_sched_tick(int inidle)
> } while (read_seqretry(&xtime_lock, seq));
>
> if (rcu_needs_cpu(cpu) || printk_needs_cpu(cpu) ||
> - arch_needs_cpu(cpu)) {
> + arch_needs_cpu(cpu) || nohz_ratelimit(cpu)) {
> next_jiffies = last_jiffies + 1;
> delta_jiffies = 1;
> } else {

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