linux-kernel - Re: Please revert [PATCH] user of the jiffies rounding patch: Slab

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Message-ID: <Pine.LNX.4.64.0704301042580.6343@schroedinger.engr.sgi.com>
Date:	Mon, 30 Apr 2007 10:43:30 -0700 (PDT)
From:	Christoph Lameter <clameter@....com>
To:	Arjan van de Ven <arjan@...ux.intel.com>
cc:	akpm@...l.org, linux-kernel@...r.kernel.org
Subject: Re: Please revert [PATCH] user of the jiffies rounding patch: Slab

On Sat, 28 Apr 2007, Arjan van de Ven wrote:

> > Hmmm... Yes but that looks like it comes from a different function. Slab
> > calls
> > 
> >  __round_jiffies_relative(HZ, cpu))
> > 
> > And its description says:
> > 
> > /**
> >  *
> >  * The exact rounding is skewed for each processor to avoid all
> >  * processors firing at the exact same time, which could lead
> >  * to lock contention or spurious cache line bouncing.
> 
> 
> > This is exactly the wrong thing to do.
> 
> 
> is it?

Umm you did not read the last bit of the description? It talks about 
firing all timers on all cpus at once.
 
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