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 10:59:55 +0200 [thread overview]
Message-ID: <20051020085955.GB2903@elte.hu> (raw)
In-Reply-To: <Pine.LNX.4.58.0510200443130.27683@localhost.localdomain>
* Steven Rostedt <rostedt@goodmis.org> wrote:
> static inline nsec_t __get_nsec_offset(void)
> {
> cycle_t cycle_now, cycle_delta;
> nsec_t ns_offset;
>
> /* read clocksource */
> cycle_now = read_clocksource(clock);
>
> /* calculate the delta since the last timeofday_periodic_hook */
> cycle_delta = (cycle_now - cycle_last) & clock->mask;
>
> /* convert to nanoseconds */
> ns_offset = cyc2ns(clock, ntp_adj, cycle_delta);
>
> /* Special case for jiffies tick/offset based systems
> * add arch specific offset
> */
> ns_offset += arch_getoffset();
>
> return ns_offset;
> }
>
> cycle_now is 32 bits. If the clocksource overflows (which it can in
> 30 seconds) the cyclec_delta will be wrong.
isnt cycle_t 64 bits?
Ingo
next prev parent reply other threads:[~2005-10-20 8:59 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-10-19 14:59 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 [this message]
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
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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