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

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Date:	Mon, 26 Oct 2009 11:25:36 -0700
From:	Mike Travis <travis@....com>
To:	Dmitry Adamushko <dmitry.adamushko@...il.com>
CC:	Tigran Aivazian <tigran@...azian.fsnet.co.uk>,
	Ingo Molnar <mingo@...e.hu>,
	Thomas Gleixner <tglx@...utronix.de>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Jack Steiner <steiner@....com>,
	"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



Dmitry Adamushko wrote:
> 2009/10/24 Tigran Aivazian <tigran@...azian.fsnet.co.uk>:
>> On Sat, 24 Oct 2009, Dmitry Adamushko wrote:
>>>> -       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.
>> The reason for printing them is that the pf (possibly others?) can change by the update and so the log has this info handy.
> 
> We might store the old sig/pf/revision set as well, export them via
> /sys or/and print them at update-to-new-microcode time.
> 
> If it's really so useful to have this info in the log and, at the same
> time, to avoid the flood of messages (which, I guess for the majority
> of systems, are the same) at startup time, we might delay the printout
> until the end of microcode_init(). Then do something like this:
> 
> microcode cpu0: up to date version sig, pf, rev          // let's say,
> it was updated by BIOS
> microcode cpus [1 ... 16] : update from sig, pf, rev to sig, pf2, rev2.
> 
> Anyway, my humble opinion, is that (at the very least) the current
> patch should be accompanied by a similar version for amd.

I could add it for AMD but I can't test it, and I'm always reluctant to
change things I can't verify.

Thanks,
Mike

> 
> 
>> Kind regards
>> Tigran
> 
> 
> -- Dmitry
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