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Re: _clear_page semantics

To: Carsten Langgaard <>
Subject: Re: _clear_page semantics
From: Ralf Baechle <>
Date: Wed, 10 Jan 2001 13:34:39 -0200
In-reply-to: <>; from on Wed, Jan 10, 2001 at 09:08:08AM +0100
References: <> <>
User-agent: Mutt/1.2.5i
On Wed, Jan 10, 2001 at 09:08:08AM +0100, Carsten Langgaard wrote:

> You are absolutely right, it is implementation dependent.
> I just tend to use the mips32 implementation for my R4000s as well, and here 
> as
> Ralf mention it is performance improving.
> Actually we have included a CPU option flag (MIPS_CPU_CACHE_CDEX), what tells 
> us
> if the CPU has the Create_Dirty_Exclusive CACHE operation available.
> So we should probably use it, now it is here :-)

Homework for somebody with some time at his hands - we have a large number
of unrolled loops for all sorts of cache variations in r4xx0.c.  Benchmark
if they actually improve performance.  I wouldn't wonder if due to a large
number of pipeline stalls in one of those routines the whole unrolling
business doesn't buy us anything.


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