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To:     Hans de Goede <hdegoede@redhat.com>
Cc:     "Martin K. Petersen" <martin.petersen@oracle.com>,
        Kate Hsuan <hpa@redhat.com>, Jens Axboe <axboe@kernel.dk>,
        Damien Le Moal <damien.lemoal@wdc.com>,
        Tor Vic <torvic9@mailbox.org>, linux-ide@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v5] libata: Add ATA_HORKAGE_NO_NCQ_ON_AMD for Samsung
 860 and 870 SSD.
From:   "Martin K. Petersen" <martin.petersen@oracle.com>
Organization: Oracle Corporation
Message-ID: <yq14kb24e97.fsf@ca-mkp.ca.oracle.com>
References: <20210901151643.13562-1-hpa@redhat.com>
        <3e26e7a5-0d99-b993-d5ce-aa517e1bf1bb@redhat.com>
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Date:   Thu, 02 Sep 2021 23:21:52 -0400
In-Reply-To: <cd75fa32-8c4d-664e-5adb-f2f325d3c58e@redhat.com> (Hans de
        Goede's message of "Thu, 2 Sep 2021 22:50:04 +0200")
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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...

-- 
Martin K. Petersen	Oracle Linux Engineering