From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>,
Linux Kernel Development <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] PATCH: add framework for ndelay (nanoseconds)
Date: 06 Feb 2003 15:53:05 +0000 [thread overview]
Message-ID: <1044546783.10374.4.camel@irongate.swansea.linux.org.uk> (raw)
In-Reply-To: <20030206174944.A17905@jurassic.park.msu.ru>
On Thu, 2003-02-06 at 14:49, Ivan Kokshaysky wrote:
> > Wouldn't it make more sense to call the parameter `nsecs' (or `ns')?
>
> There are more serious problems with this implementation:
> 1) It's *very* imprecise. Even on an 1 GHz CPU and with HZ = 100 precision
> is ~86 nsec. With HZ = 1000 it's almost unusable on *any* CPU.
HZ = 1000 isn't a 2.4 thing.
> As of current 2.4, there is the only user of ndelay() - ide_execute_command()
> that calls ndelay(400). Why udelay(1) cannot be used instead?
Why waste 500nS every IDE command as opposed to doing the job right ? The initial
ndelay() is a quick implementation. If you don't like it implement a better one,
if your box isnt fast implement it as udelay.
In the 2.5 tree I also hope we can avoid the ndelay in some cases
Alan
next prev parent reply other threads:[~2003-02-06 14:45 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <200302040533.h145Xqq19457@hera.kernel.org>
2003-02-05 14:34 ` Geert Uytterhoeven
2003-02-06 14:49 ` Ivan Kokshaysky
2003-02-06 15:53 ` Alan Cox [this message]
2003-02-06 15:05 ` Ivan Kokshaysky
2003-02-06 17:41 ` Ross Biro
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