Date: Thu, 25 Mar 2004 20:09:45 +0100
From: Ingo Molnar <mingo@elte.hu>
To: Andi Kleen <ak@suse.de>
Cc: "Nakajima, Jun" <jun.nakajima@intel.com>,
       Rick Lindsley <ricklind@us.ibm.com>, piggin@cyberone.com.au,
       linux-kernel@vger.kernel.org, akpm@osdl.org, kernel@kolivas.org,
       rusty@rustcorp.com.au, anton@samba.org, lse-tech@lists.sourceforge.net,
       mbligh@aracnet.com
Subject: Re: [Lse-tech] [patch] sched-domain cleanups, sched-2.6.5-rc2-mm2-A3
Message-ID: <20040325190944.GB12383@elte.hu>
References: <7F740D512C7C1046AB53446D372001730111990F@scsmsx402.sc.intel.com> <20040325154011.GB30175@wotan.suse.de>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20040325154011.GB30175@wotan.suse.de>
User-Agent: Mutt/1.4.1i
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1128
Lines: 28


* Andi Kleen <ak@suse.de> wrote:

> It doesn't do load balance in wake_up_forked_process() and is
> relatively non aggressive in balancing later. This leads to the
> multithreaded OpenMP STREAM running its childs first on the same node
> as the original process and allocating memory there. [...]

i believe the fix we want is to pre-balance the context at fork() time. 
I've implemented this (which is basically just a reuse of
sched_balance_exec() in fork.c, and the related namespace cleanups), 
could you give it a go:

  http://redhat.com/~mingo/scheduler-patches/sched-2.6.5-rc2-mm2-A5

another solution would be to add SD_BALANCE_FORK.

also, the best place to do fork() blancing is not at
wake_up_forked_process() time, but prior doing the MM copy. This patch
does it there. At wakeup time we've already copied all the pagetables
and created tons of dirty cachelines.

	Ingo
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/