Re: Some IDE issues with 2.6.28 on PC-Engines ALIX2

[Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>]

On Tuesday 06 January 2009, Alan Cox wrote:
> >    Judging on what you have posted, IDE driver would not probably give 
> > any speed improvement, only soewhat lesser memory footprint...
> 
> Except he is also using USB storage so the shared stack with the libata
> code is already loaded ...

Doesn't really matter because libata itself is quite heavy:

$ size drivers/ata/built-in.o drivers/ide/built-in.o
   text    data     bss     dec     hex filename
  84100    6584    4196   94880   172a0 drivers/ata/built-in.o
  50198    1032     240   51470    c90e drivers/ide/built-in.o

[ I'm pretty sure that runtime memory footprint is also lower for IDE. ]

Possible additional gains if usb-storage wouldn't be needed:

$ size drivers/scsi/built-in.o

   text    data     bss     dec     hex filename
  61136    4660     532   66328   10318 drivers/scsi/built-in.o

This is with Linus' tree from today plus "IDE updates part 3" pull request
posted today + CS5536 IDE host driver.  Enabled config options:

* libata

CONFIG_ATA=y
CONFIG_ATA_ACPI=y
CONFIG_ATA_SFF=y
CONFIG_PATA_CS5536=y

* IDE

CONFIG_IDE_GD=y
CONFIG_IDE_GD_ATA=y
CONFIG_BLK_DEV_IDEACPI=y
CONFIG_IDE_TASK_IOCTL=y
CONFIG_BLK_DEV_IDEDMA_SFF=y
CONFIG_BLK_DEV_IDEPCI=y
CONFIG_BLK_DEV_IDEDMA_PCI=y
CONFIG_BLK_DEV_CS5536=y
CONFIG_BLK_DEV_IDEDMA=y

* SCSI

CONFIG_SCSI=y
CONFIG_SCSI_DMA=y
CONFIG_BLK_DEV_SD=y
CONFIG_SCSI_MULTI_LUN=y
CONFIG_SCSI_WAIT_SCAN=m

--
Thanks,
Bart