From: robert.jarzmik@free.fr (Robert Jarzmik)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] optimize ktime_divns for constant divisors
Date: Wed, 03 Dec 2014 21:16:27 +0100 [thread overview]
Message-ID: <87zjb4zdyc.fsf@free.fr> (raw)
In-Reply-To: <alpine.LFD.2.11.1412031424150.470@knanqh.ubzr> (Nicolas Pitre's message of "Wed, 3 Dec 2014 14:43:06 -0500 (EST)")
Nicolas Pitre <nicolas.pitre@linaro.org> writes:
> Let ktime_divns() use do_div() inline whenever the divisor is constant
> and small enough. This will make things like ktime_to_us() and
> ktime_to_ms() much faster.
Hi Nicolas,
I suppose the "small enough" is linked to the "!(div >> 32)" in your patch. Can
I have the rationale which brought up this value, and if that value is universal
across architectures (ie. x86/ppc/arm/...) ?
And when you say "much faster", do you have figures to add to your commit
message ?
Cheers.
--
Robert
next prev parent reply other threads:[~2014-12-03 20:16 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-12-03 19:43 [PATCH] optimize ktime_divns for constant divisors Nicolas Pitre
2014-12-03 20:03 ` Arnd Bergmann
2014-12-04 7:23 ` Nicolas Pitre
2014-12-04 12:02 ` Arnd Bergmann
2014-12-04 13:46 ` Nicolas Pitre
2014-12-04 14:56 ` Arnd Bergmann
2014-12-04 16:47 ` Nicolas Pitre
[not found] ` <OF0EDEDB1C.C03829F7-ON48257DA5.00062083-48257DA5.0007628B@zte.com.cn>
2014-12-05 4:30 ` Nicolas Pitre
2014-12-05 10:08 ` Arnd Bergmann
2014-12-05 17:15 ` Nicolas Pitre
2014-12-03 20:16 ` Robert Jarzmik [this message]
2014-12-03 20:37 ` Nicolas Pitre
2014-12-05 18:00 ` Nicolas Pitre
2014-12-05 21:03 ` Arnd Bergmann
2014-12-18 21:21 ` John Stultz
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