After receiving Robert Cohens mail concerning
"[BENCH] Problems with IO throughput and fairness with 2.4.10 and 2.4.9-ac15"
I replied about the possibility to increase READAHEAD again.
But since I was running the -ac16 (with swapoff patch) I decided to try it
First my attempts were not that sucessful. Changing /proc/sys/vm/max-readahead
did not have any visible effect... (why not???)
Then I found /proc/ide/hda/settings
and changed "file_readahead:511" but got wery strange results...
The start is very good but suddenly the HD starts to sound strange. A check
with vmstat shows that there is a huge amount of context switches...
Going back to zero (global) readahead did not help.
So I rebooted the computer for more careful testing.
vmstat-3 is output from vmstat 3
file_readahead.settings is how I change the file_readahead
The test I perform, for each value of file_readahead, is a diff between
two huge, but identical, files.
-- Roger Larsson Skellefteċ Sweden
This archive was generated by hypermail 2b29 : Sun Sep 30 2001 - 21:01:07 EST