how to enable cache flushes for hard disk?

[kaimi]

Sorry, I found out that the great gap of performance between PC and TARGET
seems no relations to cache flushes feature.
The hd on target does not support cache flushes, I attached a supported hd
on target just now, but the performance is very bad as well.

[root at test tmp]# dmesg | grep flush
hda: cache flushes supported
[root at Dvmicro tmp]# ./hdparm -T /dev/hda

/dev/hda:
 Timing cached reads:    68 MB in  2.04 seconds =  33.25 MB/sec

While it can reach to 1.7GB/sec on PC, how can I get such a good performance
on TARGET? please
thanks

On 5/22/07, Tito <farmatito at tiscali.it> wrote:
>
> On Tuesday 22 May 2007 10:34:43 kaimi wrote:
> > Another question, on my pc, the hd supports cache flushes, it shows:
> >
> > [root at localhost linux-2.6.20-dm]# hdparm -T /dev/hdb
> >
> > /dev/hdb:
> >  Timing cached reads:   3344 MB in  2.00 seconds = 1671.72 MB/sec
> >
> > and my target board does not support cache flushed, it shows:
> > [root at test tmp]# ./hdparm -T /dev/hda
> >
> > /dev/hda:
> >  Timing cached reads:    68 MB in  2.04 seconds =  33.30 MB/sec
> >
> > I don't know if this feature is the inducement, I want to disable this
> > feature on pc, what's the command? thanks
>
> Maybe man hdparm:
>
>
>        -W     Disable/enable  the  IDE  drive´s write-caching feature
> (default
>               state is undeterminable; manufacturer/model specific).
>
> ciao,
> Tito
> >
> > On 5/22/07, kaimi <dishui at gmail.com> wrote:
> > >
> > > hi,all
> > >     I want to enable cache flushes for my hd on s3c2410 & linux-2.6.20
> ,
> > > ide_id_has_flush_cache() return 0 because cfs_enable_2 is 0x201, while
> it
> > > needs 0x3000, I found out that 0x201 was from 512 bytes of id
> > > info,implemented in static void ata_input_data(ide_drive_t *drive,
> void
> > > *buffer, u32 wcount)
> > > the question is, does it mean my hd does not support cache flush on hw
> > > layer? if not, how to enable?
> > > thanks for the coming help!
> > >
> > > Rgrds
> > > Kaimi
> > >
> > >
> >
>
>
>
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