Re: x86_64 ten times slower than i386

From: H. Peter Anvin
Date: Mon Nov 05 2007 - 12:27:39 EST


Bo Brantén wrote:

On Sat, 3 Nov 2007, Matt Mackall wrote:

This is typically due to a problem with the setup of your MTRRs. Try

This is the output from cat /proc/mtrr

reg00: base=0x00000000 ( 0MB), size=2048MB: write-back, count=1
reg01: base=0x80000000 (2048MB), size=1024MB: write-back, count=1
reg02: base=0xc0000000 (3072MB), size= 256MB: write-back, count=1
reg03: base=0xcf800000 (3320MB), size= 8MB: uncachable, count=1
reg04: base=0xcf700000 (3319MB), size= 1MB: uncachable, count=1

Confusing! Your maximum would be 3072+256M = 3328M, except that because of the uncachable MTRRs (presumably stolen memory for video), the maximum is 3319M.

-hpa
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