I have two machines with VIA chipsets. Recent 2.5
kernels boot with "DMA disabled".
On Athlon, hdparm -tT /dev/hda is about 8 times higher
on 2.4 than 2.5 kernels. hdparm -i says dma is (on) though.
I tried CONFIG_BLK_DEV_IDEDMA_FORCED=y, but that didn't
eliminated the "DMA disabled" message. Other IDE settings are:
CONFIG_IDE=y
CONFIG_BLK_DEV_IDE=y
CONFIG_BLK_DEV_IDEDISK=y
CONFIG_IDEDISK_MULTI_MODE=y
CONFIG_BLK_DEV_IDECD=m
CONFIG_BLK_DEV_IDEPCI=y
CONFIG_BLK_DEV_IDEDMA_PCI=y
CONFIG_IDEDMA_PCI_AUTO=y
CONFIG_BLK_DEV_IDEDMA=y
CONFIG_IDEDMA_AUTO=y
CONFIG_BLK_DEV_IDE_MODES=y
boot message:
VP_IDE: IDE controller at PCI slot 00:07.1
VP_IDE: chipset revision 6
VP_IDE: not 100%% native mode: will probe irqs later
VP_IDE: VIA vt82c686b (rev 40) IDE UDMA100 controller on pci00:07.1
ide0: BM-DMA at 0xd000-0xd007, BIOS settings: hda:DMA, hdb:pio
ide1: BM-DMA at 0xd008-0xd00f, BIOS settings: hdc:DMA, hdd:pio
hda: IC35L040AVER07-0, ATA DISK drive
hda: IRQ probe failed (0xffffffba)
hda: DMA disabled
ide0 at 0x1f0-0x1f7,0x3f6 on irq 14
lspci
00:00.0 Host bridge: VIA Technologies, Inc. VT8363/8365 [KT133/KM133] (rev 03)
00:01.0 PCI bridge: VIA Technologies, Inc. VT8363/8365 [KT133/KM133 AGP]
00:07.0 ISA bridge: VIA Technologies, Inc. VT82C686 [Apollo Super South] (rev 40)
00:07.1 IDE interface: VIA Technologies, Inc. VT82C586B PIPC Bus Master IDE (rev 06)
00:07.4 Bridge: VIA Technologies, Inc. VT82C686 [Apollo Super ACPI] (rev 40)
I also have a K6/2 with a VIA chipset. 2.5.34 and earlier were fine.
2.5.34-mm4 and subsequent 2.5.x kernels boot with "DMA disabled".
lspci
00:00.0 Host bridge: VIA Technologies, Inc. VT82C598 [Apollo MVP3] (rev 04)
00:01.0 PCI bridge: VIA Technologies, Inc. VT82C598/694x [Apollo MVP3/Pro133x AGP]
00:07.0 ISA bridge: VIA Technologies, Inc. VT82C586/A/B PCI-to-ISA [Apollo VP] (rev 47)
00:07.1 IDE interface: VIA Technologies, Inc. Bus Master IDE (rev 06)
The K6/2 boots with:
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 00:07.1
VP_IDE: chipset revision 6
VP_IDE: not 100% native mode: will probe irqs later
VP_IDE: VIA vt82c586b (rev 47) IDE UDMA33 controller on pci00:07.1
ide0: BM-DMA at 0xe000-0xe007, BIOS settings: hda:DMA, hdb:DMA
ide1: BM-DMA at 0xe008-0xe00f, BIOS settings: hdc:DMA, hdd:DMA
hda: Maxtor 51536U3, ATA DISK drive
hdb: ATAPI CDROM, ATAPI CD/DVD-ROM drive
hda: DMA disabled
hdb: DMA disabled
ide0 at 0x1f0-0x1f7,0x3f6 on irq 14
--
Randy Hron
http://home.earthlink.net/~rwhron/kernel/bigbox.html
On Wed, 2003-01-08 at 05:16, [email protected] wrote:
> I have two machines with VIA chipsets. Recent 2.5
> kernels boot with "DMA disabled".
It turns it on again but forgets to tell you. Its on the fix list
bu tfor 2.4 first
>> Recent 2.5 kernels boot with "DMA disabled".
> It turns it on again but forgets to tell you. Its on the fix list
> but for 2.4 first
Actual throughput on Athlon is better then hdparm lets on. A
dd test on 2.5.53-mm1 shows about 120 MB/sec for a file that fits in
memory.
# time dd if=/dev/zero of=/tmp/junk bs=4M count=100
100+0 records in
100+0 records out
real 0m3.312s
user 0m0.002s
sys 0m3.267s
# ls -lh /tmp/junk
-rw-r--r-- 1 root root 400M Jan 13 21:43 /tmp/junk
hdparm -tT on the K6/2 shows similar throughput between 2.4 and 2.5.
Maybe my hdparm is just wacky on 2.5.
2.4.20-pre3-jam1:
/dev/hda:
Timing buffer-cache reads: 128 MB in 0.70 seconds =182.86 MB/sec
Timing buffered disk reads: 64 MB in 2.07 seconds = 30.92 MB/sec
2.5.53-mm1
/dev/hda:
Timing buffer-cache reads: 128 MB in 7.20 seconds = 17.78 MB/sec
Timing buffered disk reads: 64 MB in 19.66 seconds = 3.26 MB/sec
--
Randy Hron
http://home.earthlink.net/~rwhron/kernel/bigbox.html
On Mon January 13 2003 18:49, [email protected] wrote:
>
> 2.4.20-pre3-jam1:
>
> /dev/hda:
> Timing buffer-cache reads: 128 MB in 0.70 seconds =182.86 MB/sec
> Timing buffered disk reads: 64 MB in 2.07 seconds = 30.92 MB/sec
>
> 2.5.53-mm1
>
> /dev/hda:
> Timing buffer-cache reads: 128 MB in 7.20 seconds = 17.78 MB/sec
> Timing buffered disk reads: 64 MB in 19.66 seconds = 3.26 MB/sec
2.5.53-mm1 had a dud patch in it which made part of the kernel think HZ=100,
other parts think HZ=1000, depending on whether the .c file happened to
include config.h before including param.h.
Hence your nice 10x discrepancy.