Re: ata_std_qc_defer not good enough for FIS-based switching ?

[Mark Lord <liml@rtr.ca>]

Mark Lord wrote:
..
> For the first time ever, I can now *heavily* mix PIO commands
> with NCQ/non-NCQ DMA commands, to drives on an attached PM
> (well, two attached PMs even), and the thing doesn't croak.
> Woo-hoo!
..

Here is the simple torture test I'm using for this.
It might be fun for others to try something similar on the other LLDs
which have PMP support:

1. QuadCore CPU, with 4GB of RAM (lots of simultaneous threads).

2. In one window, do this (lots of overlapping PIO commands):
    while ( true ) ; do for d in /dev/sd? ; do bash -c "hdparm -C $d &" ; done  ;  sleep 0.1 ; done

3. In a second window, do this (lots of overlapping DMA/NCQ reads):
    while (true) ; do  for d in /dev/sd? ; do bash -c "hdparm -t $d &" ; done ; sleep 6 ; done

Or something like that.

Cheers