Marinos Yannikos wrote:
>
> Hi,
>
> our brand-new ICP GDT8523RZ controller with 6 disks peaks out at
> 45MB/s under 2.4.10, while with 2.2.19 it reaches 85MB/s (seq.
> read performance). It should realistically be able to reach
> at least 150-200MB/s in this configuration
Well that's pretty bad, isn't it?
Some things which it would be interesting to try out:
- Disable CONFIG_HIGHMEM in your kernel config, see
what that does.
- Try linux-2.4.13 -- 2.4.10 was a bit of a dog (this may make
a difference if the driver uese the new PCI DMA API,
but it doesn't explain why 2.2.x does so much better).
- Profile the kernel. You may enable profiling by booting
the kernel with the LILO option `profile=1'.
Then, making sure that /boot/System.map reflects the
running kernel, run this little script
#!/bin/sh
TIMEFILE=/tmp/$(basename $1).time
sudo readprofile -r
time "$@"
readprofile -v -m /boot/System.map | sort -n +2 | tail -40 | tee $TIMEFILE
echo created $TIMEFILE
With something like:
~/kern-prof.sh cp some_huge_file /dev/null
-
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This archive was generated by hypermail 2b29 : Wed Oct 31 2001 - 21:00:21 EST