On 04/14/2016 05:43 PM, Tejun Heo wrote:
Hello, Hannes.
On Thu, Apr 14, 2016 at 07:44:19AM +0200, Hannes Reinecke wrote:
Hehe. No, it isn't, if you look closely.
(Or make that: it _shouldn't_, and I've messed it up)
(That's what the 'fpdma' parameter is for)
The benefit is not so much for normal operations, but it'll give us
a performance improvements on SMR drives where we need to issue
READ LOG DMA EXT rather frequently. There we really want to have
them as NCQ commands.
I'm still a bit confused. Isn't it part of EH? If so, the path is
never traveled with other commands in flight and thus whether a
command is NCQ or not doesn't make any difference. The only thing
it'd do is making devices which advertise the capability but don't get
it quite right fail.
For this patch, yes, you are right.
However, the ZAC enablement patches later on submit READ LOG EXT
commands (for REPORT ZONES), and _they_ benefit from NCQ encapsulation.
Cheers,
Hannes
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