We are using RedHat's 2.4.3-12 kernel for our Alpha machines and
stumbled over a bad performance problem with raw devices:
Our test results (with a couple of disks and controllers ;-) were:
Kernel 2.2.18 ~200MB/s 95% idle
Kernel 2.4.3-12(RH) ~105MB/s 0% idle
Kernel 2.4.11-pre3 ~173MB/s 28% idle
The 2.2.18 kernel is using the SGI raw device patches.
I saw that Andrea had a patch for 2.4.3aa where he could improve the RAW
I/O performance significantly. I looked at the patch and I could not
apply it to 2.4.3-12 because of conflicts which I was not able to
I also looked at 2.4.10 and saw that Andreas patch was not in there.
How can I get a similar RAW-IO performance with 2.4.3-12 as I had with
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