linux-kernel - Re: [PATCH 6/8] SGI x86_64 UV: Limit the number of microcode messages

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Date:	Sat, 24 Oct 2009 22:09:42 +0200
From:	Dmitry Adamushko <dmitry.adamushko@...il.com>
To:	Mike Travis <travis@....com>
Cc:	Ingo Molnar <mingo@...e.hu>, Thomas Gleixner <tglx@...utronix.de>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Jack Steiner <steiner@....com>,
	Tigran Aivazian <tigran@...azian.fsnet.co.uk>,
	"H. Peter Anvin" <hpa@...or.com>, x86@...nel.org,
	Andreas Mohr <andi@...as.de>, Hugh Dickins <hugh@...itas.com>,
	Hannes Eder <hannes@...neseder.net>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 6/8] SGI x86_64 UV: Limit the number of microcode messages

2009/10/24 Mike Travis <travis@....com>:
> Limit number of microcode messages of the form:
>
> [   50.887135] microcode: CPU0 sig=0x206e5, pf=0x4, revision=0xffff001
>
> [ ... ]
>
> --- linux.orig/arch/x86/kernel/microcode_intel.c
> +++ linux/arch/x86/kernel/microcode_intel.c
> @@ -165,7 +165,9 @@
>        /* get the current revision from MSR 0x8B */
>        rdmsr(MSR_IA32_UCODE_REV, val[0], csig->rev);
>
> -       printk(KERN_INFO "microcode: CPU%d sig=0x%x, pf=0x%x, revision=0x%x\n",
> +       if (cpu_num < 4 || !limit_console_output(false))
> +               printk(KERN_INFO
> +                       "microcode: CPU%d sig=0x%x, pf=0x%x, revision=0x%x\n",
>                        cpu_num, csig->sig, csig->pf, csig->rev);
>

Hmm, I guess we wouldn't lose a lot by simply removing those messages
completely. Per-cpu pf/revision is available via /sys anyway.

Alternatively, we might move the output into
microcode_core.c::collect_cpu_info() (or even microcode_init_cpu()) so
that the same logic is also applied for amd and do something as
following:

don't print if a cpu info is equal to the info of CPU#0. I guess, any
non-0 cpu would be even better as the microcode for cpu#0 can be
loaded by BIOS, if I'm not mistaken. But then we can only be sure
about the presence of cpu#0.

Anyway, it's not worthy of any additional complexity so I'd say let's
just remove the output :-)


-- Dmitry
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