Re: Kernel 2.5.40 DMA and mm issues

Nick Sanders (sandersn@btinternet.com)
Fri, 4 Oct 2002 09:51:33 +0100


On Friday 04 October 2002 9:02 am, Andrew Morton wrote:
> szonyi calin wrote:
> > ...
> > Here is /proc/meminfo after killing the updatedb:
> > MemTotal: 125576 kB
> > MemFree: 5540 kB
> > MemShared: 0 kB
> > Buffers: 21092 kB
> > Cached: 25124 kB
> > SwapCached: 1888 kB
> > Active: 15388 kB
> > Inactive: 33268 kB
> > HighTotal: 0 kB
> > HighFree: 0 kB
> > LowTotal: 125576 kB
> > LowFree: 5540 kB
> > SwapTotal: 248968 kB
> > SwapFree: 246892 kB
> > Dirty: 64 kB
> > Writeback: 0 kB
> > Mapped: 2512 kB
> > Slab: 69712 kB
> > Committed_AS: 3348 kB
> > PageTables: 192 kB
> > ReverseMaps: 2314
>
> That looks reasonable for an updatedb run.
>
> > hda: DMA disabled
>
> This is probably why it's taking tons of system time.
> -

I get the same 'DMA disabled' messages with 2.5 but DMA is never actually
disabled so I wouldn't rely on them being accurate (see below)

Uniform Multi-Platform E-IDE driver Revision: 7.00alpha2
ide: Assuming 33MHz system bus speed for PIO modes; override with idebus=xx
VP_IDE: IDE controller at PCI slot 00:11.1
PCI: Hardcoded IRQ 14 for device 00:11.1
VP_IDE: chipset revision 6
VP_IDE: not 100% native mode: will probe irqs later
ide: Assuming 33MHz system bus speed for PIO modes; override with idebus=xx
VP_IDE: VIA vt8233a (rev 00) IDE UDMA133 controller on pci00:11.1
ide0: BM-DMA at 0xff00-0xff07, BIOS settings: hda:DMA, hdb:DMA
ide1: BM-DMA at 0xff08-0xff0f, BIOS settings: hdc:DMA, hdd:pio
hda: WDC WD400BB-00CAA0, ATA DISK drive
hdb: TOSHIBA DVD-ROM SD-M1402, ATAPI CD/DVD-ROM drive
hda: DMA disabled
hdb: DMA disabled
ide0 at 0x1f0-0x1f7,0x3f6 on irq 14
hdc: LITE-ON LTR-24102B, ATAPI CD/DVD-ROM drive
hdc: DMA disabled
ide1 at 0x170-0x177,0x376 on irq 15
hda: host protected area => 1
hda: 78165360 sectors (40021 MB) w/2048KiB Cache, CHS=4865/255/63, UDMA(100)
hda: hda1 hda2 hda3 hda4 < hda5 hda6 >
-----------------------------------------------------------------------------------------------------------
gandalf:/home/sandersn# hdparm /dev/hda

/dev/hda:
multcount = 0 (off)
IO_support = 1 (32-bit)
unmaskirq = 1 (on)
using_dma = 1 (on)
keepsettings = 0 (off)
readonly = 0 (off)
readahead = 256 (on)
geometry = 4865/255/63, sectors = 78165360, start = 0
------------------------------------------------------------------------------------------------------------
gandalf:/home/sandersn# hdparm -tT /dev/hda

/dev/hda:
Timing buffer-cache reads: 128 MB in 0.43 seconds =299.77 MB/sec
Timing buffered disk reads: 64 MB in 1.52 seconds = 42.22 MB/sec

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