Re: x86: improve default idle

[Andrew Morton <akpm@linux-foundation.org>]

On Fri, 18 Apr 2008 17:37:02 GMT
Linux Kernel Mailing List <linux-kernel@vger.kernel.org> wrote:

> Gitweb:     http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=13af4836b3914b23946f6a8982934e2c828c183f
> Commit:     13af4836b3914b23946f6a8982934e2c828c183f
> Parent:     f5149a49f994e5c469ac398af7cdeb8eb612d3a4
> Author:     Ingo Molnar <mingo@elte.hu>
> AuthorDate: Wed Apr 2 13:23:22 2008 +0200
> Committer:  Ingo Molnar <mingo@elte.hu>
> CommitDate: Thu Apr 17 17:41:34 2008 +0200
> 
>     x86: improve default idle
>     
>     Signed-off-by: Ingo Molnar <mingo@elte.hu>
> ---
>  arch/x86/kernel/process_32.c |    8 --------
>  arch/x86/kernel/process_64.c |    8 --------
>  2 files changed, 0 insertions(+), 16 deletions(-)
> 
> diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
> index 08c41ed..3903a8f 100644
> --- a/arch/x86/kernel/process_32.c
> +++ b/arch/x86/kernel/process_32.c
> @@ -113,16 +113,8 @@ void default_idle(void)
>  
>  		local_irq_disable();
>  		if (!need_resched()) {
> -			ktime_t t0, t1;
> -			u64 t0n, t1n;
> -
> -			t0 = ktime_get();
> -			t0n = ktime_to_ns(t0);
>  			safe_halt();	/* enables interrupts racelessly */
>  			local_irq_disable();
> -			t1 = ktime_get();
> -			t1n = ktime_to_ns(t1);
> -			sched_clock_idle_wakeup_event(t1n - t0n);
>  		}
>  		local_irq_enable();
>  		current_thread_info()->status |= TS_POLLING;
> diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
> index 4f40272..e75ccc8 100644
> --- a/arch/x86/kernel/process_64.c
> +++ b/arch/x86/kernel/process_64.c
> @@ -107,16 +107,8 @@ void default_idle(void)
>  	smp_mb();
>  	local_irq_disable();
>  	if (!need_resched()) {
> -		ktime_t t0, t1;
> -		u64 t0n, t1n;
> -
> -		t0 = ktime_get();
> -		t0n = ktime_to_ns(t0);
>  		safe_halt();	/* enables interrupts racelessly */
>  		local_irq_disable();
> -		t1 = ktime_get();
> -		t1n = ktime_to_ns(t1);
> -		sched_clock_idle_wakeup_event(t1n - t0n);
>  	}
>  	local_irq_enable();
>  	current_thread_info()->status |= TS_POLLING;

Ingo, what's going on?  There is no way that this patch is so obvious that
it doesn't even need a changelog.

Was this ever sent to a mailing list for review?  I can't find it, so my
last remaining means of understanding the change does not work.

(And if it _did_ have a changelog, I could at least google for the
changelog's text, but even that tool is frustrated here).