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From: Pavel Machek <pavel@suse.cz>
To: Chris Snook <csnook@redhat.com>
Cc: Jeff Hansen <x@jeffhansen.com>,
	torvalds@linux-foundation.org, linux-kernel@vger.kernel.org,
	mingo@elte.hu
Subject: Re: x86_32 tsc/pit and hrtimers
Date: Thu, 9 Oct 2008 19:20:09 +0200	[thread overview]
Message-ID: <20081009172009.GD1370@ucw.cz> (raw)
In-Reply-To: <48ECFEDC.90305@redhat.com>

Hi!

>> Can you please tell me if this is supposed to work, and I just have a
>> poorly configured kernel; or if TSC/PIT drivers were not designed to work
>> this way in the first place.  If it wasn't designed to do this, do you
>> have any tips on implementing this, since I'll be needing to do that?
>>
> This is not supposed to work, but it might be worthwhile to add a boot 
> option to force the kernel to trust the TSC, as hardware that lacks any 
> high-res timers also tends to be primitive enough that the TSC can be 
> trusted, if it exists.  If you patch out the CLOCK_SOURCE_MUST_VERIFY 
> flag on the TSC, do you get correctly-functioning high-res timers on this 
> system?

Untrue. Unstable tsc dates back to pentium MMX times.

-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

      parent reply	other threads:[~2008-10-09 17:20 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-10-07 22:41 x86_32 tsc/pit and hrtimers Jeff Hansen
2008-10-08 18:41 ` Chris Snook
2008-10-08 19:46   ` Jeff Hansen
2008-10-08 20:25     ` Chris Snook
2008-10-08 21:43       ` [PATCH] " Jeff Hansen
2008-10-08 21:47         ` Randy.Dunlap
2008-10-08 21:47         ` Chris Snook
2008-10-08 21:56           ` Jeff Hansen
2008-10-09  7:14             ` Thomas Gleixner
2008-10-09 18:39               ` Chris Snook
2008-10-09 19:18                 ` Thomas Gleixner
2008-10-09 19:45                   ` Jeff Hansen
2008-10-09 19:53                     ` Thomas Gleixner
2008-10-09 20:45                       ` Alok kataria
2008-10-09 21:03                         ` Chris Snook
2008-10-09 21:18                           ` Jeff Hansen
2008-10-09 22:03                             ` Alok Kataria
2008-10-09 21:53                           ` Alok Kataria
2008-10-09 22:50                             ` Chris Snook
2008-10-09 23:22                               ` Alok Kataria
2008-10-09 23:37                                 ` Chris Snook
2008-10-10 14:24                                   ` Jeff Hansen
2008-10-09 17:20   ` Pavel Machek [this message]

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