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From: Ingo Molnar <mingo@elte.hu>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: john stultz <johnstul@us.ibm.com>,
	tglx@linutronix.de, linux-kernel@vger.kernel.org
Subject: Re: Ktimer / -rt9 (+custom) monotonic_clock going backwards.
Date: Thu, 20 Oct 2005 17:55:25 +0200	[thread overview]
Message-ID: <20051020155525.GA10360@elte.hu> (raw)
In-Reply-To: <Pine.LNX.4.58.0510200605170.27683@localhost.localdomain>


* Steven Rostedt <rostedt@goodmis.org> wrote:

> > I just switched cycle_t to u64 and hackbench no longer makes the time go
> > backwards.
> >
> > John, would this cause any problems to keep cycle_t at s64?
> 
> I mean at u64.

ugh. There's both cycles_t and cycle_t. We should unify the two and it 
should be 64-bit. The faster systems get, the sooner the 32-bit counter 
overflows. 64-bit systems are keeping 32-bit compatibility for quite 
some time to come. So with an 8GHz CPU the 32-bit cycle_t would wrap in 
like 500 msecs, way too fast to rely on ... (even with a 4GHz CPUs it's 
only one second.)

i've made cycle_t u64 and have uploaded -rt14.

	Ingo

  reply	other threads:[~2005-10-20 15:55 UTC|newest]

Thread overview: 44+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-10-19 14:59 Ktimer / -rt9 (+custom) monotonic_clock going backwards Steven Rostedt
2005-10-19 15:10 ` Thomas Gleixner
2005-10-19 18:39   ` john stultz
2005-10-20  6:55     ` Steven Rostedt
2005-10-20  7:34       ` Ingo Molnar
2005-10-20  7:46         ` Steven Rostedt
2005-10-20  8:01           ` Ingo Molnar
2005-10-20  8:56             ` Steven Rostedt
2005-10-20  8:59               ` Ingo Molnar
2005-10-20  9:04                 ` Steven Rostedt
2005-10-20  9:05                   ` Steven Rostedt
2005-10-20 10:05                   ` Steven Rostedt
2005-10-20 10:05                     ` Steven Rostedt
2005-10-20 15:55                       ` Ingo Molnar [this message]
2005-10-20 16:09                         ` Steven Rostedt
2005-10-20 16:45                       ` john stultz
2005-10-20 16:58                         ` Steven Rostedt
2005-10-20 17:05                           ` john stultz
2005-10-20 19:32                         ` Ingo Molnar
2005-10-20 20:05                           ` john stultz
2005-10-20 20:54                             ` Ingo Molnar
2005-10-21  6:03                           ` Steven Rostedt
2005-10-21  7:49                             ` Thomas Gleixner
2005-10-21  7:57                               ` Steven Rostedt
2005-10-21  8:00                               ` ktimer API Steven Rostedt
2005-10-21  8:09                                 ` Thomas Gleixner
2005-10-21 18:09                             ` Ktimer / -rt9 (+custom) monotonic_clock going backwards john stultz
2005-10-21 18:15                               ` Thomas Gleixner
2005-10-20 22:06           ` George Anzinger
2005-10-20  6:19   ` Steven Rostedt
2005-10-20 14:34   ` Steven Rostedt
2005-10-20 15:18     ` Steven Rostedt
2005-10-20 15:23       ` Steven Rostedt
2005-10-20 16:01       ` Steven Rostedt
2005-10-19 15:11 ` Ingo Molnar
2005-10-20  6:38   ` Steven Rostedt
2005-10-20  6:56     ` Ingo Molnar
2005-10-19 15:21 ` Daniel Walker
2005-10-20  6:39   ` Steven Rostedt
2005-10-20 15:02     ` Daniel Walker
2005-10-20 22:19       ` George Anzinger
2005-10-20 23:23         ` john stultz
2005-10-19 16:44 ` Frank Sorenson
2005-10-20  6:43   ` Steven Rostedt

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