Re: [PATCH v5] libata: Add ATA_HORKAGE_NO_NCQ_ON_AMD for Samsung 860 and 870 SSD.

[Tor Vic]

Hi,

I saw that v2 (?) of this patch has made it into stable, which
is quite reasonable given the number of bug reports.
Are there any plans to "enhance" this patch once sufficient data
on controller support/drive combinations has been collected?

I didn't run any benchmarks to see whether performance has changed,
but I now have this on 5.14.6:

  /sys/class/ata_device/dev3.0/trim:forced_unqueued
  /sys/class/ata_device/dev4.0/trim:forced_unqueued

Before:

  /sys/class/ata_device/dev3.0/trim:queued
  /sys/class/ata_device/dev4.0/trim:queued

These correspond to 860 Pro and 860 Evo, connected to a X570
mainboard (AMD FCH controller).
Note that neither before nor after this commit I had any problems
with these drives.


On 03.09.21 03:21, Martin K. Petersen wrote:
> Hans,
>
> > I just realized that all newer Samsung models are non SATA...
> >
> > Still I cponsider it likely that some of the other vendors also
> > implement queued trim support and there are no reports of issues
> > with the other vendors' SSDs.
>
> When I originally worked on this the only other drive that supported
> queued trim was a specific controller generation from Crucial/Micron.
>
> Since performance-sensitive workloads quickly moved to NVMe, I don't
> know if implementing queued trim has been very high on the SSD
> manufacturers' todo lists. FWIW, I just checked and none of the more
> recent SATA SSD drives I happen to have support queued trim.
>
> Purely anecdotal: I have a Samsung 863 which I believe is
> architecturally very similar to the 860. That drive clocked over 40K
> hours as my main git repo/build drive until it was retired last
> fall. And it ran a queued fstrim every night.
>
> Anyway. I am not against disabling queued trim for these drives. As far
> as I'm concerned it was a feature that didn't quite get enough industry
> momentum. It just irks me that we don't have a good understanding of why
> it works for some and not for others...