Re: [RFC][PATCH] at91_ide driver

[Sergei Shtylyov <sshtylyov@ru.mvista.com>]

Hello, I wrote:

>>> the PIO transfer speeds (very significantly) though I'm not sure of 
>>> the current state of affairs...
>>>     
>>
>> 16bit only performance is identical (as you'd expect)
>
>   Well, I don't know what to expect, having seen figures like 0.5 (or 
> 1.5) MB/s cited on this list...

   Instead of going to bed, I tried booting FC8 (2.6.23.y) off DVD in 
rescue mode and suppressing libata's DMA use: hdparm -t topped at around 
1 MB/s from both SATA hard drive and PATA DVD drive with sata_sil driven 
the former and pata_atiixp the latter... I wasn't able to compare 
results with IDE core of course.

>> identical with the 32bit pio patches applied
>>   
> 32bit is now
>
>   Hm, I didn't realize 32-bit I/O really can really boost the IDE 
> speed. I vaguely remember (or misremember) benchmarking drives under 
> DOS (many years ago) with and without 32-bit access enabled in the 
> BIOS Setup and not seeing any significant differences. Perhpas it's 
> worth to re-benchmark this in Linux if I find the time...

   With hdparm being able to control that via its -c option when using 
IDE driver, it shouldn't take much time...

MBR, Sergei