Re: [PATCH] Inhibit NMI watchdog when Alt-SysRq-T operation isunderway.

From: Andrew Morton
Date: Fri Jul 20 2007 - 17:06:47 EST


On Fri, 20 Jul 2007 07:18:23 -0400
Konrad Rzeszutek <konrad@xxxxxxxxxx> wrote:

> I tested your patch along with mine and found two things out:
>
> 1). Missing this patch (for i386 platform)
>
> diff --git a/arch/i386/kernel/traps.c b/arch/i386/kernel/traps.c
> index 90da057..9f3a7ff 100644
> --- a/arch/i386/kernel/traps.c
> +++ b/arch/i386/kernel/traps.c
> @@ -207,6 +207,7 @@ static void print_trace_address(void *da
> {
> printk("%s [<%08lx>] ", (char *)data, addr);
> print_symbol("%s\n", addr);
> + touch_nmi_watchdog();
> }

ok...

> static struct stacktrace_ops print_trace_ops = {
>
>
> 2). If I run Alt-SysRq-t about 5000 times in a loop, the slow down
> with this change is about 5%. Is this a big issue? (This was
> testing both i686 and x86_64).
>

I'm surprised. I assume this was when it was printing to a high-speed
device? console or netconsole?

I don't think we need to spend too much time optimising sysrq-T performance ;)
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