>
> OK Here goes.
> I have a Jetway J-542B MB with 64MB RAM and a K6-2/333 CPU. I am running
> kernel 2.3.37.
>
> 00:00.0 Host bridge: Acer Laboratories Inc. M1541 (rev 04)
> 00:01.0 PCI bridge: Acer Laboratories Inc.: Unknown device 5243 (rev 04)
> 00:07.0 ISA bridge: Acer Laboratories Inc. M1533 (rev b4)
> 00:0f.0 IDE interface: Acer Laboratories Inc. M5229 (rev 20)
>
> >From dmesg I have,
>
> ALI15X3: MultiWord DMA enabled
> hda: Maxtor 90680D4, 2014MB w/256kB Cache, CHS=826/255/63, (U)DMA
^^^^
This means that kernel decides your chipset is not UDMA capable, while the
drive is...
Note, that driver author (from ALI) suggested that for M5229 rev. <= 0x20
UDMA is "not stable", so it should be disabled by the driver...
> So far, so good?
> Here are my hdparm -tT /dev/hda results,
>
> /dev/hda:
> Timing buffer-cache reads: 128 MB in 3.04 seconds =42.11 MB/sec
> Timing buffered disk reads: 64 MB in 9.73 seconds = 6.87 MB/sec
Quite standard results for mword DMA mode 2 ...
> I am disappointed by the 6.87MB/sec. Shouldn't it be much more? With
> using_dma=0 I get 4-5MB/sec. NB: The Maxtor HD is a UDMA/Mode2 device and
> its specs say,
>
> DATA TRANSFER RATE:
> To/From Interface: ....................... Up to 33.0 MBs
> To/From Media: ........................... Up to 18.6 MBs
In UDMA/Mode2, yes. But you must use apropriate (UDMA-capable) controller
...
> A couple of supplementary points/questions: My kernel is reporting
> 'ALI15X3: MultiWord DMA enabled' rather than 'ALI15X3: Ultra DMA enabled'
> as Meelis' does. Any ideas why?
This chipset revision is not UDMA capable...
> According to Western Digital's UDMA info webpage, 'multiword DMA mode 2'
> should give a max. data-rate of 16.6MB/sec - much more than I get.
My WD drive with same chipset revision reports about 8.5 MB/s.
On unloaded AXP system (CMD646) with IBM drive I observe ~12 MB/s.
I observe, that for many BIOSes timings are calculated basing on maximum
possible PCI clock rather than on currently being set one.
It effects in a bit worse transfer results. To test it you can try:
1. put the idebus=... parameter to the kernel during boot
(I use idebus=30, as set on my MoBo)
2. hdparm -d0 ...
3. hdpatm -p ... # calculate new timings
4. hdparm -X34 ...
5. hdparm -d1 ...
Difference shouldn't be meaningfull, but slightly better.
Cheers
-- ======================================================================= Andrzej M. Krzysztofowicz ankry@mif.pg.gda.pl phone (48)(58) 347 14 61 Faculty of Applied Phys. & Math., Technical University of Gdansk- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.rutgers.edu Please read the FAQ at http://www.tux.org/lkml/
This archive was generated by hypermail 2b29 : Sat Jan 15 2000 - 21:00:20 EST