2004-Dec-15

I have some Linux systems that boot saying:

ide: Assuming 33MHz system bus speed for PIO modes; override with idebus=xx

One system is very slow and near unusable -- although it has a 1363.734 MHz processor. I am trying to track down if it is a hardware or software issue. It does have limited physical memory (91920 usable), but is still slow even before it uses virtual memory. I am going to install hdparm to see how that helps.

One one slower system, I get:

reed@puget:/usr/pkgsrc/wip/hdparm$ sudo hdparm -t /dev/hda

/dev/hda:
Timing buffered disk reads:  10 MB in  3.04 seconds =   3.29 MB/sec
reed@puget:/usr/pkgsrc/wip/hdparm$ sudo hdparm -T /dev/hda

/dev/hda:
Timing cached reads:    96 MB in  2.08 seconds =  46.05 MB/sec

Now on the slow system:

montecristo:/home/packages$ sudo hdparm -t /dev/hda

/dev/hda:
Timing buffered disk reads:   16 MB in  3.29 seconds =   4.87 MB/sec
montecristo:/home/packages$ sudo hdparm -T /dev/hda

/dev/hda:
Timing cached reads:   796 MB in  2.01 seconds = 396.47 MB/sec

The cached reads were a lot faster, but the buffered disk reads were slower.

And the slow system has:

montecristo:/home/packages$ sudo hdparm  -v /dev/hda

/dev/hda:
multcount    =  8 (on)
IO_support   =  1 (32-bit)
unmaskirq    =  1 (on)
using_dma    =  0 (off)
keepsettings =  0 (off)
readonly     =  0 (off)
readahead    = 256 (on)
geometry     = 65535/16/63, sectors = 41110142976, start = 0

When I try to use DMA:

montecristo:/home/packages$ sudo hdparm  -d1 /dev/hda

/dev/hda:
setting using_dma to 1 (on)
HDIO_SET_DMA failed: Operation not permitted
using_dma    =  0 (off)

I think I need to build a kernel with DMA support? But it looks like I already do:

CONFIG_GENERIC_ISA_DMA=y
CONFIG_BLK_DEV_IDEDMA_PCI=y
# CONFIG_BLK_DEV_IDEDMA_FORCED is not set
CONFIG_IDEDMA_PCI_AUTO=y
# CONFIG_IDEDMA_ONLYDISK is not set
CONFIG_BLK_DEV_ADMA=y
CONFIG_BLK_DEV_IDEDMA=y
# CONFIG_IDEDMA_IVB is not set
CONFIG_IDEDMA_AUTO=y

I think I need "via support". I am not sure ...