acd0 vs cd0 (ATAPICAM)

Hi,

I'm running FreeBSD 5-CURRENT (Aug. 28 2003) on a P3 733MHz, 768MB ram
with a LG DVD-RW/DVD-RAM burner. I would like to know why ATAPICAM is so
slow with my system.

DMA is enabled for my ATAPI burner.

When I'm copying something using cd0, my system is very slow. (e.g. my
mouse moves very very slowly)


Here is the results of my tests:

Using mkisofs with acd0:
------------------------

# mount_cd9660 /dev/acd0 /dvdrom
# time mkisofs -dvd-video -o /divers/acd0.iso /dvdrom/
  0.24% done, estimate finish Fri Sep  5 22:33:31 2003
  0.48% done, estimate finish Fri Sep  5 22:33:30 2003
  ...
  99.54% done, estimate finish Fri Sep  5 22:26:55 2003
  99.78% done, estimate finish Fri Sep  5 22:26:55 2003
Total translation table size: 0
Total rockridge attributes bytes: 0
Total directory bytes: 4096
Path table size(bytes): 42
Max brk space used c2e4
2064560 extents written (4032 Mb)

real    14m2.575s
user    0m16.109s
sys     2m43.673s


Using mkisofs with cd0 (ATAPICAM):
----------------------------------

# mount_cd9660 /dev/cd0 /dvdrom
# time mkisofs -dvd-video -o /divers/cd0.iso /dvdrom/
  0.24% done, estimate finish Fri Sep  5 23:01:41 2003
  0.48% done, estimate finish Fri Sep  5 22:58:14 2003
  ...
  99.54% done, estimate finish Fri Sep  5 22:59:20 2003
  99.78% done, estimate finish Fri Sep  5 22:59:21 2003
Total translation table size: 0
Total rockridge attributes bytes: 0
Total directory bytes: 4096
Path table size(bytes): 42
Max brk space used c2e4
2064560 extents written (4032 Mb)

real    25m9.761s
user    0m22.586s
sys     3m13.866s



Using dd with acd0
------------------

root_at_guillaume# time dd if=/dev/acd0 of=/divers/lepianiste.img bs=2k
2064816+0 records in
2064816+0 records out
4228743168 bytes transferred in 2646.410996 secs (1597916 bytes/sec)

real    44m6.434s
user    0m5.517s
sys     6m27.386s


Using dd with cd0 (ATAPICAM)
----------------------------

My computer reboot after ~ 15 or 20 min.




Output from dmesg:
------------------
...
ad0: 29325MB <Maxtor 6E030L0> [59582/16/63] at ata0-master UDMA66
ad1: 19595MB <QUANTUM FIREBALLP LM20.5> [39813/16/63] at ata0-slave
UDMA66
acd0: DVDR <HL-DT-ST DVDRAM GMA-4020B> at ata1-master UDMA33
cd0 at ata1 bus 0 target 0 lun 0
cd0: <HL-DT-ST DVDRAM GMA-4020B A108> Removable CD-ROM SCSI-0 device
cd0: 33.000MB/s transfers
cd0: cd present [2064816 x 2048 byte records]
Mounting root from ufs:/dev/ad0s2a
...



Thanks


Guillaume
amyfoub_at_videotron.ca