Re: bad networking related lag in v2.6.22-rc2

[Anant Nitya <kernel@prachanda.info>]

On Tuesday 22 May 2007 11:52:33 Ingo Molnar wrote:
> * Anant Nitya <kernel@prachanda.info> wrote:
> > > I think I already found the bug, please try if this patch helps.
> >
> > Sorry, but this patch is not helping here. I recompiled the kernel
> > with this patch but same load pattern still make system to crawl.
> >
> > Here is the link for script I use to shape traffic.
> >
> > http://cybertek.info/taitai/adslbwopt.sh
>
> could you also apply the fix for the softirq problem below, to make sure
> it does not interact?
>
> 	Ingo
>
> Index: linux/kernel/sched.c
> ===================================================================
> --- linux.orig/kernel/sched.c
> +++ linux/kernel/sched.c
> @@ -4212,9 +4212,7 @@ int __sched cond_resched_softirq(void)
>  	BUG_ON(!in_softirq());
>
>  	if (need_resched() && system_state == SYSTEM_RUNNING) {
> -		raw_local_irq_disable();
> -		_local_bh_enable();
> -		raw_local_irq_enable();
> +		local_bh_enable();
>  		__cond_resched();
>  		local_bh_disable();
>  		return 1;

Hi Ingo
Above patch does solve __ soft_irq_pending __ problem. I am running this patch 
with kernel 2.6.21.1 since last day doing all kinda things but haven't 
encountered any __ NOHZ: local_softirq_pending __. But network lag that I am 
seeing since 2.6.22-rc1 is still there even with this patch applied. If you 
need any more information please do ask. Meanwhile I will do gitbisect as 
suggested by linus to find out the specific commit that introduced this 
problem and will inform once I find it. Its good to see system running 
without any __ local_softirq_problem __ :)

Regards
Ananitya

-- 
Out of many thousands, one may endeavor for perfection, and of
those who have achieved perfection, hardly one knows Me in truth.
				-- Gita Sutra Of Mysticism