From: Tony Breeds <tony@bakeyournoodle•com>
To: Nathan Lynch <ntl@pobox•com>
Cc: linuxppc-dev@ozlabs•org
Subject: Re: [PATCH] kill useless SMT code in prom_hold_cpus
Date: Tue, 15 Jul 2008 12:22:03 +1000 [thread overview]
Message-ID: <20080715022202.GD20457@bakeyournoodle.com> (raw)
In-Reply-To: <20080708223631.GP9594@localdomain>
On Tue, Jul 08, 2008 at 05:36:31PM -0500, Nathan Lynch wrote:
> I think this code that counts SMT threads and compares against NR_CPUS
> is an artifact of pre-powerpc-merge ppc64. We care about starting
> only primary threads in the OF client code.
<snip>
> - prom_printf("%x : starting cpu hw idx %x... ", cpuid, reg);
> + prom_printf("starting cpu hw idx %x... ", reg);
If we remove this, where else can we see the mapping of hardware IDs
to logical cpu IDs? This is useful on POWER4 (at least where they can be
different).
<snip>
> - if (cpuid > NR_CPUS)
> - prom_printf("WARNING: maximum CPUs (" __stringify(NR_CPUS)
> - ") exceeded: ignoring extras\n");
> -
I think this printf() is valuable, if your boot a 128 thread machine on
a kernel with NR_CPUS=64, this is the only messaage you get to indicate
that you're wasting 64 threads, and how to resolve it.
Yours Tony
linux.conf.au http://www.marchsouth.org/
Jan 19 - 24 2009 The Australian Linux Technical Conference!
next prev parent reply other threads:[~2008-07-15 2:22 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-07-08 22:36 [PATCH] kill useless SMT code in prom_hold_cpus Nathan Lynch
2008-07-15 2:05 ` Benjamin Herrenschmidt
2008-07-15 2:24 ` Nathan Lynch
2008-07-15 4:53 ` Benjamin Herrenschmidt
2008-07-15 2:22 ` Tony Breeds [this message]
2008-07-15 4:55 ` Nathan Lynch
2008-07-15 4:59 ` Tony Breeds
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