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From: Borislav Petkov <bp@alien8.de>
To: Ingo Molnar <mingo@kernel.org>
Cc: Len Brown <lenb@kernel.org>,
	x86@kernel.org, linux-pm@vger.kernel.org,
	linux-kernel@vger.kernel.org, Len Brown <len.brown@intel.com>
Subject: Re: [PATCH 2/2] x86: speed cpu_up by quirking cpu_init_udelay
Date: Fri, 8 May 2015 10:23:20 +0200	[thread overview]
Message-ID: <20150508082319.GA4137@pd.tnic> (raw)
In-Reply-To: <20150508075111.GA5403@gmail.com>

On Fri, May 08, 2015 at 09:51:11AM +0200, Ingo Molnar wrote:
> > +static const struct x86_cpu_id init_udelay_ids[] = {
> > +	{ X86_VENDOR_INTEL, 0x6, X86_MODEL_ANY, X86_FEATURE_ANY, 0 },
> > +	{ X86_VENDOR_AMD, 0x16, X86_MODEL_ANY, X86_FEATURE_ANY, 0 },
> > +	{ X86_VENDOR_AMD, 0x15, X86_MODEL_ANY, X86_FEATURE_ANY, 0 },
> > +	{ X86_VENDOR_AMD, 0x14, X86_MODEL_ANY, X86_FEATURE_ANY, 0 },
> > +	{ X86_VENDOR_AMD, 0x12, X86_MODEL_ANY, X86_FEATURE_ANY, 0 },
> > +	{ X86_VENDOR_AMD, 0x11, X86_MODEL_ANY, X86_FEATURE_ANY, 0 },
> > +	{ X86_VENDOR_AMD, 0x10, X86_MODEL_ANY, X86_FEATURE_ANY, 0 },
> > +	{ X86_VENDOR_AMD, 0xF, X86_MODEL_ANY, X86_FEATURE_ANY, 0 },
> > +	{}
> > +};
> 
> So since especially AMD likes to iterate the family upwards, why not 
> make this a simple open ended check:
> 
> 	if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL &&
> 	    boot_cpu_data.x86 >= 6 ||
> 	    boot_cpu_data.x86_vendor == X86_VENDOR_AMD &&
> 	    boot_cpu_data.x86 >= 15) {
> 
> 		... 0 delay ...
> 	}
> 
> ... which is much smaller and more future proof?

I was about to say that...

-- 
Regards/Gruss,
    Boris.

ECO tip #101: Trim your mails when you reply.
--

  reply	other threads:[~2015-05-08  8:23 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-05-08  6:37 [PATCH 0/2 v2] speeding up cpu_up() Len Brown
2015-05-08  6:37 ` [PATCH 1/2] x86: replace cpu_up hard-coded mdelay with variable udelay Len Brown
2015-05-08  6:37   ` [PATCH 2/2] x86: speed cpu_up by quirking cpu_init_udelay Len Brown
2015-05-08  7:51     ` Ingo Molnar
2015-05-08  8:23       ` Borislav Petkov [this message]
2015-05-08  8:32     ` Borislav Petkov
2015-05-08 18:15       ` Len Brown
2015-05-08 18:27         ` Borislav Petkov
2015-05-09  7:22         ` Ingo Molnar
2015-05-09  7:24         ` Ingo Molnar
2015-05-09  8:04           ` Borislav Petkov

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