Alan Cox wrote:
On Mon, Sep 06, 2004 at 10:11:51AM -0700, Jesse Keating wrote:
>I guess a better question: With kernel 2.6, is there any need to have a
>specific ia32e vs amd64 kernel? Are all the differences worked out at
>runtime and thus a non-issue? Thanks.
em64t as Intel currently call it is pretty close to the x86-64 architecture
so its not too bad a clone. It lacks prefetch/prefetchw which can also be
used by some fancy user space stuff like image processors. It also lacks
a hardware IOMMU so you may have performance problems going above about 3.5Gb
of RAM depending on your other hardware.
Sorry for following up on an old thread...
I have a Xeon/EM64T machine with 4G.
FC3-32bit installs without problems, 4G available.
FC3 x86-64 doesn't install, no disks are found.
If I boot FC3 x86-64 installation with mem=3072M,
there are no problems.
I have to add mem=3072M to grub after the installation
to get a running system.
The funny thing is, if I write mem=4096M, it still
boots, but only 3G memory is available.
I can see from /proc/iomem that there are devices
starting at the 3G address, so my guess is that
I've run into the problem described above.
Is there any way to get a x86-64 kernel to use all
Mogens Kjaer, Carlsberg A/S, Computer Department
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