profiling data of lacking ICH2 (was: poor ATA disk speed with ICH2)

Bjoern Koenig bkoenig at cs.tu-berlin.de
Fri Sep 10 16:14:18 PDT 2004


Hello again,

I built a recent GENERIC kernel (1.413.2.2 2004/09/09 23:10:48 scottl) with
high resolution kernel profiling (config -pp). I ran a little shell script
in single-user mode which looks like

[...]
kgmon -rB
dd if=/dev/zero of=/usr/out bs=4096 count=262144
kgmon -hpr
[...]

and created the following output with gprof:
 
http://www.alpha-tierchen.de/dateien/gprof.out.txt
(I'm sorry for posting this external link, but I didn't like to append
~15000 lines to this mail ;-)

This is my dmesg:
http://www.alpha-tierchen.de/dateien/dmesg.txt

hw.ata.wc=1
hw.ata.ata_dma=1

The dd command told ~15 MB/s without profiling (~500 kB/s with profiling).

There is absolutely no failure with the hard disk and the controller,
because after that I installed a 4.10-RELEASE into the same slice and it
works pretty fine (~37 MB/s). I repeated this test at another position on
hard disk _completely_ ... and as expected I got similar results.

I hope the profiling data helps. I would like to see a gprof output of a
system which works correctly, otherwise I have no possibility to compare. I
have the time and motivation to analyse them and point out the difference.

best regards
Björn König




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