FreeBSD and poor ata performance

[fandino]

Subhro wrote:
> sysctl -a | grep dma ?

vfs.iodmaxidle: 120
vfs.nfs.iodmax: 20
hw.ata.ata_dma: 1
hw.ata.atapi_dma: 1
hw.busdma.free_bpages: 128
hw.busdma.reserved_bpages: 0
hw.busdma.active_bpages: 0
hw.busdma.total_bpages: 128
hw.busdma.total_bounced: 0
hw.busdma.total_deferred: 0
dev.atdma.0.%driver: atdma
dev.atdma.0.%location: handle=\_SB_.PCI0.PX40.DMA1
dev.atdma.0.%pnpinfo: _HID=PNP0200 _UID=0
dev.atdma.0.%parent: acpi0

# atacontrol list

ATA channel 0:
     Master:  ad0 <ST340823A/3.32> ATA/ATAPI revision 4
     Slave:  acd0 <HL-DT-ST DVDRAM GSA-4081B/A100> ATA/ATAPI revision 5
ATA channel 1:
     Master:  ad2 <ST340810A/5.33> ATA/ATAPI revision 6
     Slave:  acd1 <TOSHIBA DVD-ROM SD-M1612/1004> ATA/ATAPI revision 5
ATA channel 2:
     Master:  ad4 <ST340014A/3.54> ATA/ATAPI revision 6
     Slave:   ad5 <Maxtor 6E040L0/NAR61EA0> ATA/ATAPI revision 7
ATA channel 3:
     Master:  ad6 <ST340014A/3.06> ATA/ATAPI revision 6
     Slave:   ad7 <Maxtor 6E040L0/NAR61EA0> ATA/ATAPI revision 7

# atacontrol mode 0
Master = UDMA100
Slave  = UDMA33

# atacontrol mode 1
Master = UDMA100
Slave  = UDMA33

# atacontrol mode 2
Master = UDMA100
Slave  = UDMA100

# atacontrol mode 3
Master = UDMA100
Slave  = UDMA100