Re: [PATCH] 2.6 workaround for Athlon/Opteron prefetch errata

[Dave Jones]

On Thu, Sep 18, 2003 at 09:43:31AM +0200, Pavel Machek wrote:

 > > The user space problem worries me more, because the expectation
 > > is that if CPUID says the program can use perfetch, it could
 > > and should regardless of what the kernel decided to do here.
 > 
 > User programs should not rely on cpuid;

Depends. /dev/cpu/x/cpuid is preferred over cpuinfo, as it remains
constant across kernel versions.

 > they should read /proc/cpuinfo exactly because this kind of errata.

We don't do any change to /proc/cpuinfo in this case. As I mentioned
in an earlier mail, the only way you could disable prefetch in this way
would be by reporting the entire sse/3dnow instruction sets as unavailable
which is overkill.

With Andi's fix, userspace programs doing prefetch get fixed up
transparently, making this a non-issue.

		Dave

-- 
 Dave Jones     http://www.codemonkey.org.uk
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