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From: Andi Kleen <ak@muc.de>
To: Rusty Russell <rusty@rustcorp.com.au>
Cc: lkml - Kernel Mailing List <linux-kernel@vger.kernel.org>,
	dmitry.torokhov@gmail.com
Subject: Re: [PATCH] Turn rdmsr, rdtsc into inline functions, clarify names
Date: 6 Aug 2006 05:16:43 +0200
Date: Sun, 6 Aug 2006 05:16:43 +0200	[thread overview]
Message-ID: <20060806031643.GA43490@muc.de> (raw)
In-Reply-To: <1154832963.29151.21.camel@localhost.localdomain>

> 	Please reconsider.  This isn't about being pretty, it's about not
> having hidden side-effects,

I wouldn't call it hidden, it's well defined in the architecture.

> and having typechecking.

The existing code will already reject any non integer and I don't
see a particular need to be more strict than that.

> > If you feel a need to clean up I would suggest you convert more
> > users over to the ll variants which take a single 64bit value
> > instead of two 32bit ones.
> 
> You mean the l and ll variants?  The 64 bit variants are rdmsrl and
> rdtscll, not to be confused with rdtscl, which returns the lower 32
> bits.  This confusion caused the x86_64 bug in gameport.c 

Why does gameport access MSRs or TSCs? That sounds like a bug in itself.

<looking at the code> 

This whole thing is broken, e.g. on a preemptive kernel when the
code can switch CPUs 

Dmitry, I would suggest to convert it over to do_gettimeofday and remove
all the architecture ifdefs.

Or maybe just remove it completely.  Who cares about the speed of a gameport 
anyways? And why can't they measure it in user space? 

> See why I want to fix these names?

No.

> So if you would prefer u64 rdtsc64(), u32 rdtsc_low(), u64 rdmsr64(int
> msr), u32 rdmsr_low(int msr), I can convert everyone to that, although
> it's a more invasive change...

I think things are most fine right now, except that I think most users
of high low should be converted to work directly on 64bit quantities.

-Andi

  parent reply	other threads:[~2006-08-06  3:16 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <1154771262.28257.38.camel@localhost.localdomain>
2006-08-06  2:38 ` [PATCH] Turn rdmsr, rdtsc into inline functions, clarify names Andi Kleen
2006-08-06  2:56   ` Rusty Russell
2006-08-06  2:58     ` H. Peter Anvin
2006-08-06  3:09       ` Rusty Russell
2006-08-06  3:11         ` H. Peter Anvin
2006-08-06  3:49           ` Rusty Russell
2006-08-06  3:16     ` Andi Kleen [this message]
2006-08-06  3:52       ` Rusty Russell
2006-08-06 14:58         ` Andi Kleen
2006-08-07  2:43       ` Dmitry Torokhov
2006-08-07  8:48         ` Andi Kleen
2006-08-07 11:09           ` Vojtech Pavlik
2006-08-07 12:28             ` Andi Kleen
2006-08-07 12:48               ` Vojtech Pavlik
2006-08-07 12:56                 ` Andi Kleen
2006-08-07 13:18                   ` Vojtech Pavlik
2006-08-07 13:32                   ` Dmitry Torokhov
2006-08-07 15:01                     ` Andi Kleen
2006-08-07 15:19                   ` Andreas Mohr
2006-08-07 15:57                     ` Andi Kleen
2006-08-07 16:04                       ` Vojtech Pavlik
2006-08-07 16:12                         ` Andi Kleen
2006-08-07 19:22                           ` Vojtech Pavlik
2006-08-14 20:13                 ` Pavel Machek
2006-08-07 11:07         ` Vojtech Pavlik

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