From: Roman Zippel <zippel@linux-m68k.org>
To: john stultz <johnstul@us.ibm.com>
Cc: linux-kernel@vger.kernel.org, akpm@linux-foundation.org
Subject: Re: [PATCH 7/8] Remove current_tick_length()
Date: Sat, 15 Mar 2008 05:18:24 +0100 (CET) [thread overview]
Message-ID: <Pine.LNX.4.64.0803150511580.1791@scrub.home> (raw)
In-Reply-To: <1205552909.6122.63.camel@localhost.localdomain>
Hi,
On Fri, 14 Mar 2008, john stultz wrote:
> > Why would someone do something silly like this?
>
> Its not a huge deal, but we've seen globally scoped timekeeping
> variables misused either accidentally or intentionally. Awhile back ppc
> was corrupting time_offset by using it for a timezone offset value.
>
> So I think its a valid maintainability issue.
ppc used to do a whole lot more than that, so I don't think that counts as
a valid example.
tick_length is overwritten at every timer and modifying it would have
barely any effect compared to other values which are already exported.
> > > Is there any additional rational for this change?
> >
> > Useless bloat?
>
> I agree its a trade off. But do you have performance numbers to make the
> maintainability trade off worth it? (I admit, it is used in the
> timer_interrupt, so it may very well be worth it, but we might want to
> check first).
It depends on the architecture, but it's effects regularly executed code
and every byte counts.
bye, Roman
next prev parent reply other threads:[~2008-03-15 4:18 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-03-14 18:40 [PATCH 0/8] NTP updates zippel
2008-03-14 18:40 ` [PATCH 1/8] cleanup ntp.c zippel
2008-03-14 20:30 ` john stultz
2008-03-15 3:21 ` Roman Zippel
2008-03-14 18:40 ` [PATCH 2/8] NTP4 user space bits update zippel
2008-03-14 20:36 ` john stultz
2008-03-15 3:29 ` Roman Zippel
2008-03-14 18:40 ` [PATCH 3/8] increase time_freq resolution zippel
2008-03-14 18:40 ` [PATCH 4/8] increase time_offset resolution zippel
2008-03-14 18:40 ` [PATCH 5/8] support for TAI zippel
2008-03-14 20:55 ` john stultz
2008-03-14 18:40 ` [PATCH 6/8] Rename TICK_LENGTH_SHIFT to NTP_SCALE_SHIFT zippel
2008-03-14 18:40 ` [PATCH 7/8] Remove current_tick_length() zippel
2008-03-15 2:41 ` john stultz
2008-03-15 3:32 ` Roman Zippel
2008-03-15 3:48 ` john stultz
2008-03-15 4:18 ` Roman Zippel [this message]
2008-03-15 16:29 ` Ray Lee
2008-03-15 17:14 ` Roman Zippel
2008-03-18 1:01 ` john stultz
2008-03-26 1:53 ` Roman Zippel
2008-03-14 18:40 ` [PATCH 8/8] handle leap second via timer zippel
2008-03-14 20:24 ` john stultz
2008-03-15 3:18 ` Roman Zippel
2008-03-17 22:18 ` Andrew Morton
2008-03-21 14:15 ` Thomas Gleixner
2008-03-14 23:03 ` [PATCH 0/8] NTP updates john stultz
2008-03-15 3:15 ` Roman Zippel
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