From: george anzinger <george@mvista.com>
To: Russell King <rmk@arm.linux.org.uk>
Cc: Andrew Morton <akpm@zip.com.au>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] Fix jiffies_to_time[spec | val] and converse to use actual jiffies increment rather than 1/HZ
Date: Tue, 15 Apr 2003 02:25:12 -0700 [thread overview]
Message-ID: <3E9BCFF8.3050703@mvista.com> (raw)
In-Reply-To: <20030415095528.B32468@flint.arm.linux.org.uk>
Russell King wrote:
> On Tue, Apr 15, 2003 at 01:36:46AM -0700, george anzinger wrote:
>
>>In the current system (2.5.67) time_spec to jiffies, time_val to
>>jiffies and the converse (jiffies to time_val and jiffies to
>>time_spec) all use 1/HZ as the measure of a jiffie. Because of the
>>inability of the PIT to actually generate an accurate 1/HZ interrupt,
>>the wall clock is updated with a more accurate value (999848
>>nanoseconds per jiffie for HZ = 1000).
>
>
> There's an increasing amount of 64-bit math appearing here, which gcc
> has been historically bad with. Is there any chance that all this
> extra complexity can vanish for architectures which do not have this
> problem?
I suppose that is possible. On the other hand, the only 64-bit things
we leave to C are the "+" and shift.
>
--
George Anzinger george@mvista.com
High-res-timers: http://sourceforge.net/projects/high-res-timers/
Preemption patch: http://www.kernel.org/pub/linux/kernel/people/rml
prev parent reply other threads:[~2003-04-15 9:13 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-04-15 8:36 [PATCH] Fix jiffies_to_time[spec | val] and converse to use actual jiffies increment rather than 1/HZ george anzinger
2003-04-15 8:55 ` Russell King
2003-04-15 9:25 ` george anzinger [this message]
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