Re: IDE performance drop between 2.4.23 and 2.6.0 - pinpointed!

Pawel Dziekonski
2004-01-03T22:02:12Z

hi,

same problem here however it seems that i have pinpointed it )at least
for me):

root@localhost:~ # hdparm -ft /dev/hdb

/dev/hdb:
Timing buffered disk reads: 64 MB in 1.60 seconds = 39.96 MB/sec
root@localhost:~ #
root@localhost:~ # hdparm -a 256 /dev/hdb

/dev/hdb:
setting fs readahead to 256
readahead = 256 (on)
root@localhost:~ # hdparm -ft /dev/hdb

/dev/hdb:
Timing buffered disk reads: 64 MB in 1.60 seconds = 39.93 MB/sec
root@localhost:~ # hdparm -ft /dev/hdb

/dev/hdb:
Timing buffered disk reads: 64 MB in 1.74 seconds = 36.77 MB/sec
root@localhost:~ # hdparm -ft /dev/hdb

/dev/hdb:
Timing buffered disk reads: 64 MB in 1.60 seconds = 39.91 MB/sec

this is OK! (under 2.4.23-pre8 i get a little bit more than 40)
also changing redaahead to even 8192 gives simmilar results.
also changing it for hda.

now look at this:

modprobe eagle-usb (my adsl modem)
adictrl -w (load firmware to modem , synchronize etc..)

root@localhost:~ # adictrl -w
Sending options to device /proc/bus/usb/001/002
Options successfully sent to driver.
Sending DSP code to device /proc/bus/usb/001/002
DSP code successfully loaded.
Waiting for synchro...
OK .. Modem is synchronized.
root@localhost:~ #
root@localhost:~ # hdparm -ft /dev/hdb

/dev/hdb:
Timing buffered disk reads: 64 MB in 3.84 seconds = 16.67 MB/sec
root@localhost:~ #
root@localhost:~ # hdparm -ft /dev/hdb

/dev/hdb:
Timing buffered disk reads: 64 MB in 3.67 seconds = 17.42 MB/sec
root@localhost:~ #
root@localhost:~ # hdparm -ft /dev/hdb

/dev/hdb:
Timing buffered disk reads: 64 MB in 3.74 seconds = 17.09 MB/sec
root@localhost:~ # umount /proc/bus/usb/
root@localhost:~ #
root@localhost:~ #
root@localhost:~ # hdparm -ft /dev/hdb

/dev/hdb:
Timing buffered disk reads: 64 MB in 3.30 seconds = 19.39 MB/sec
root@localhost:~ # hdparm -ft /dev/hdb

/dev/hdb:
Timing buffered disk reads: 64 MB in 2.71 seconds = 23.62 MB/sec
root@localhost:~ # hdparm -ft /dev/hdb

/dev/hdb:
Timing buffered disk reads: 64 MB in 3.57 seconds = 17.91 MB/sec
root@localhost:~ # hdparm -a 8192 /dev/hdb

/dev/hdb:
setting fs readahead to 8192
readahead = 8192 (on)
root@localhost:~ # hdparm -ft /dev/hdb

/dev/hdb:
Timing buffered disk reads: 64 MB in 3.09 seconds = 20.74 MB/sec
root@localhost:~ # hdparm -ft /dev/hdb

/dev/hdb:
Timing buffered disk reads: 64 MB in 3.44 seconds = 18.59 MB/sec
root@localhost:~ # hdparm -a 8192 /dev/hda

/dev/hda:
setting fs readahead to 8192
readahead = 8192 (on)
root@localhost:~ # hdparm -ft /dev/hdb

/dev/hdb:
Timing buffered disk reads: 64 MB in 2.94 seconds = 21.78 MB/sec
root@localhost:~ # hdparm -ft /dev/hdb

/dev/hdb:
Timing buffered disk reads: 64 MB in 2.58 seconds = 24.80 MB/sec
root@localhost:~ # hdparm -ft /dev/hdb

/dev/hdb:
Timing buffered disk reads: 64 MB in 2.96 seconds = 21.63 MB/sec
root@localhost:~ # hdparm -t /dev/hdb

/dev/hdb:
Timing buffered disk reads: 64 MB in 3.59 seconds = 17.82 MB/sec
root@localhost:~ # hdparm -t /dev/hdb

disaster...

funny (? ;-) thing is that under 2.4 i have same issue...

my chipset is kt133 (via), i use uhci.

root@localhost:~ # cat /proc/interrupts
CPU0
0: 2283127 XT-PIC timer
1: 4896 XT-PIC i8042
2: 0 XT-PIC cascade
8: 1 XT-PIC rtc
9: 0 XT-PIC acpi
10: 0 XT-PIC eth0, VIA686A
11: 271497 XT-PIC uhci_hcd, uhci_hcd
12: 171840 XT-PIC bttv0, nvidia
14: 33427 XT-PIC ide0
15: 1 XT-PIC ide1
NMI: 0
ERR: 4

tested under pure 2.6.0. ac scheduler, same under noop and dead.

regards, Pawel

ps. i read the list via www so cc my the replies please. thanks.