Petr --
Hi again!
>1 problem) my SATA drive is too slow now (14MB/s - by hdparm)
> new 2.6.7 kernel uses SCSI emulation [/dev/sda]
> previous 2.6.6 kernel (50 MB/s) uses standard way [/dev/hda]
I just did a quick test copying with cp a 550.8 meg file (actual megs not
decimal megs) from one SATA drive to another and the time command. I did this
three times each in the old kernel and the new kernel, with the following
results (times in seconds):
2.6.6-1.435.2.3 2.6.7-1.494.2.2
real user sys real user sys
6.165 0.013 1.649 12.016 0.025 1.901
6.892 0.024 1.753 13.649 0.022 2.001
13.221 0.026 1.667 5.155 0.022 1.851
mean 8.759 0.021 1.690 10.273 0.023 1.918
The results are disappointing but not disastrous: the mean times are 9.5%-17%
slower in the new kernel. This still a decent showing: average 53.6 MB/s based
on real time in the new kernel, with 106.8 MB/s based on real time in the best
case (which may be a good measure of what is really disk access and not the
system being busy on other processes). Also, while system time is always higher
in the new kernel, real and user time vary a lot and the differences could be
due to sampling error. I am using an AMD Athlon FX 64-53 in an ASUS SK8V
motherboard with two Western Digital 740 10K Raptor drives.
-- Phil
