[ltp] hdparm settings?

[Nathan Kurz]

On Fri, Feb 18, 2005 at 10:47:57AM -0500, Charles E Taylor IV wrote:
> # hdparm /dev/hda
> 
> /dev/hda:
>  multcount    = 16 (on)
>  IO_support   =  1 (32-bit)
>  unmaskirq    =  1 (on)
>  using_dma    =  1 (on)
>  keepsettings =  0 (off)
>  readonly     =  0 (off)
>  readahead    = 256 (on)
>  geometry     = 16383/255/63, sectors = 40007761920, start = 0
> 
> and gives this performance:
> 
> # hdparm -t /dev/hda
> 
> /dev/hda:
>  Timing buffered disk reads:  104 MB in  3.02 seconds =  34.41 MB/sec

Interesting.  On my X30 with a 40G drive (presumed 5400 RPM), I still
get a consistent 18 MB/s, and can't get the 34 MB/s you are seeing.
Playing with it a little bit, I see that adjusting multcount (-m) from
0 to 16 does not seem to affect the transfer speed, and that
surprisingly adjusting 32-bit IO Support (-c) from off to on also has
no effect.  I had been playing with readahead set very large (set with
'blockdev'), but lowering it also seemed to have no effect.

On desktop machines I've occasionally seen the speed double when
adding 32-bit support, and since your speed is just about double mine
that seems suspicious.  Anyone know if this setup should support
32-bit IO and have any idea why it might not be?

Anyway, here's what I see on my system:

# hdparm -t /dev/hda

/dev/hda:
 Timing buffered disk reads:   56 MB in  3.10 seconds =  18.08 MB/sec

# hdparm /dev/hda

/dev/hda:
 multcount    = 16 (on)
 IO_support   =  1 (32-bit)
 unmaskirq    =  1 (on)
 using_dma    =  1 (on)
 keepsettings =  0 (off)
 readonly     =  0 (off)
 readahead    = 256 (on)
 geometry     = 65535/16/63, sectors = 78140160, start = 0

# hdparm -i /dev/hda

/dev/hda:

 Model=IC25N040ATCS04-0, FwRev=CA4OA71A, SerialNo=CSH405DCG9651B
 Config={ HardSect NotMFM HdSw>15uSec Fixed DTR>10Mbs }
 RawCHS=16383/16/63, TrkSize=0, SectSize=0, ECCbytes=4
 BuffType=DualPortCache, BuffSize=1768kB, MaxMultSect=16, MultSect=16
 CurCHS=16383/16/63, CurSects=16514064, LBA=yes, LBAsects=78140160
 IORDY=on/off, tPIO={min:240,w/IORDY:120}, tDMA={min:120,rec:120}
 PIO modes:  pio0 pio1 pio2 pio3 pio4 
 DMA modes:  mdma0 mdma1 mdma2 
 UDMA modes: udma0 udma1 udma2 udma3 udma4 *udma5 
 AdvancedPM=yes: mode=0x80 (128) WriteCache=enabled
 Drive conforms to: ATA/ATAPI-5 T13 1321D revision 3: 

Nathan Kurz
nate@verse.com