From: Roman Zippel <zippel@linux-m68k.org>
To: john stultz <johnstul@us.ibm.com>
Cc: lkml <linux-kernel@vger.kernel.org>, Ingo Molnar <mingo@elte.hu>
Subject: Re: [PATCH 1/5] split clocksource adjustment from clockosurce mult
Date: Sat, 15 Mar 2008 05:28:24 +0100 (CET) [thread overview]
Message-ID: <Pine.LNX.4.64.0803150526060.1791@scrub.home> (raw)
In-Reply-To: <1205553938.6122.79.camel@localhost.localdomain>
Hi,
On Fri, 14 Mar 2008, john stultz wrote:
> @@ -179,7 +181,7 @@ static inline cycle_t clocksource_read(struct clocksource *cs)
> static inline s64 cyc2ns(struct clocksource *cs, cycle_t cycles)
> {
> u64 ret = (u64)cycles;
> - ret = (ret * cs->mult) >> cs->shift;
> + ret = (ret * (cs->mult + cs->mult_adj)) >> cs->shift;
> return ret;
> }
This add an extra memory access and extra instruction to a code path, we
should keep as short as possible.
I'd rather add a mult_raw or mult_org and use that for your next patch.
bye, Roman
next prev parent reply other threads:[~2008-03-15 4:32 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-03-15 4:04 [PATCH 0/5] time/ntp changes john stultz
2008-03-15 4:05 ` [PATCH 1/5] split clocksource adjustment from clockosurce mult john stultz
2008-03-15 4:06 ` [PATCH 2/5] introduce CLOCK_MONOTONIC_RAW john stultz
2008-03-15 4:10 ` [PATCH 3/5] cleanups ntp.c (from Ingo) john stultz
2008-03-15 4:12 ` [PATCH 4/5] ntp.c code flow clenaups " john stultz
2008-03-15 4:15 ` [PATCH 5/5] make more ntp values static john stultz
2008-03-15 5:09 ` Roman Zippel
2008-03-15 4:52 ` [PATCH 4/5] ntp.c code flow clenaups (from Ingo) Roman Zippel
2008-03-15 5:04 ` John Stultz
2008-03-15 12:39 ` Ingo Oeser
2008-03-15 17:24 ` Roman Zippel
2008-03-15 5:06 ` [PATCH 3/5] cleanups ntp.c " Roman Zippel
2008-03-15 9:32 ` Jörg-Volker Peetz
2008-03-15 17:23 ` Roman Zippel
2008-03-15 4:50 ` [PATCH 2/5] introduce CLOCK_MONOTONIC_RAW Roman Zippel
2008-03-18 2:03 ` john stultz
2008-03-18 2:27 ` john stultz
2008-03-26 3:41 ` Roman Zippel
2008-03-15 4:28 ` Roman Zippel [this message]
2008-03-15 5:07 ` [PATCH 1/5] split clocksource adjustment from clockosurce mult John Stultz
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