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From: Borislav Petkov <bp@suse.de>
To: Andy Lutomirski <luto@amacapital.net>
Cc: x86-ml <x86@kernel.org>, Peter Zijlstra <peterz@infradead.org>,
	Steven Rostedt <rostedt@goodmis.org>,
	lkml <linux-kernel@vger.kernel.org>
Subject: Re: [RFC PATCH] x86: Kill notsc
Date: Mon, 19 Oct 2015 10:16:10 +0200	[thread overview]
Message-ID: <20151019081610.GB20028@pd.tnic> (raw)
In-Reply-To: <CALCETrX=MZKdOT+QHYPJcKe_ue-s0pjKZiYLejMPJWnXLkhv9A@mail.gmail.com>

On Sun, Oct 18, 2015 at 09:47:21PM -0700, Andy Lutomirski wrote:
> I'm a bit confused.  Is it currently the case that, if you boot a
> normal kernel on a TSC-less machine without notsc, it fails?

No, it shouldn't fail because we're checking CPUID flags.

The point of this patch is purely cleaning up stuff and getting rid
of all the notsc/tsc_disabled logic. What is more tempting, however,
is getting rid of the static key in native_sched_clock. It is almost
pointless complexity and we don't really need it.

AFAIK, only some early 486s and 586s don't have TSC and they can disable
CONFIG_X86_TSC. Which they do, actually, if you choose M486 or M586 in
Kconfig.

-- 
Regards/Gruss,
    Boris.

SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg)
-- 

  reply	other threads:[~2015-10-19  8:16 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-10-18 14:20 [RFC PATCH] x86: Kill notsc Borislav Petkov
2015-10-19  4:47 ` Andy Lutomirski
2015-10-19  8:16   ` Borislav Petkov [this message]
2015-10-21 17:58 ` Borislav Petkov
2015-10-21 19:01   ` Peter Zijlstra
2015-10-22 18:51     ` [PATCH -v2] " Borislav Petkov
2015-11-04 10:21       ` Thomas Gleixner
2015-11-04 10:29         ` Borislav Petkov
2015-11-16 18:45           ` [RFC PATCH -v2.1] " Borislav Petkov
2015-11-16 21:25             ` Thomas Gleixner
2015-11-17  5:02               ` H. Peter Anvin
2015-11-17  8:53                 ` Borislav Petkov
2015-11-17  9:11                   ` Thomas Gleixner
2015-11-17  9:33                     ` Borislav Petkov
2015-11-17 10:08                       ` Thomas Gleixner
2015-11-17 11:09                         ` Borislav Petkov

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