Re: 2.6.0 performance problems

[Mike Fedyk <mfedyk@matchmail.com>]

On Mon, Dec 29, 2003 at 08:49:07PM -0500, Thomas Molina wrote:
> On Tue, 30 Dec 2003, Martin Schlemmer wrote:
> 
> > > It's not uncommon for a laptop to have a hard disk which supports
> > > higher DMA modes than what the IDE chipset supports.
> > > My aging Intel 440BX based VAIO has a disk in the same configuration
> > > as yours, supports udma4, but chipset only goes up to udma2.
> > > 
> > 
> > Right, or as somebody else pointed out, it might not be a 80-pin cable.
> > 
> > Lets rephrase - does it also run in udma2 mode with 2.4 ?  And did
> > you check readahead?  In 2.6 it seems that a bigger value is better -
> > I for instance have to set it to 8192 to have the same performance as
> > in 2.4 ...
> 
> 8192 will be my next test.  I'm doing a compile at the moment.  It runs in 
> udma2 under both 2.4 and 2.6.  If I need an 80-pin cable then udma4 is not 
> possible for this system.  If I read the following, it is only capable of 
> 66MHz anyway:
> 
> 00:07.1 IDE interface: VIA Technologies, Inc. 
> VT82C586A/B/VT82C686/A/B/VT8233/A/C/VT8235 PIPC Bus Master IDE (rev 10) 
> (prog-if 8a [Master SecP PriP])
>         Control: I/O+ Mem- BusMaster+ SpecCycle- MemWINV- VGASnoop- 
> ParErr- Stepping- SERR- FastB2B-
>         Status: Cap+ 66Mhz- UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort-

66Mhz has nothing to do with the DMA factor (33, 66, 100, 133, etc.).
That's talking about the PCI bus, and I doubt you have a 66Mhz bus in a
laptop.