2013-04-12 18:28:09

by Asai Thambi SP

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Subject: [PATCH 2/2] mtip32xx: mtip32xx: Disable TRIM support


Temporarily disabling TRIM support until TRIM related issues
are addressed in the firmware.

Signed-off-by: Asai Thambi S P <[email protected]>
---
drivers/block/mtip32xx/mtip32xx.c | 2 ++
1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/drivers/block/mtip32xx/mtip32xx.c b/drivers/block/mtip32xx/mtip32xx.c
index d11ea92..53bad62 100644
--- a/drivers/block/mtip32xx/mtip32xx.c
+++ b/drivers/block/mtip32xx/mtip32xx.c
@@ -1560,10 +1560,12 @@ static int mtip_get_identify(struct mtip_port *port, void __user *user_buffer)
}
#endif

+#ifdef MTIP_TRIM /* Disabling TRIM support temporarily */
/* Demux ID.DRAT & ID.RZAT to determine trim support */
if (port->identify[69] & (1 << 14) && port->identify[69] & (1 << 5))
port->dd->trim_supp = true;
else
+#endif
port->dd->trim_supp = false;

/* Set the identify buffer as valid. */
--
1.7.1


2013-04-14 08:25:52

by Jens Axboe

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Subject: Re: [PATCH 2/2] mtip32xx: mtip32xx: Disable TRIM support

On Fri, Apr 12 2013, Asai Thambi S P wrote:
>
> Temporarily disabling TRIM support until TRIM related issues
> are addressed in the firmware.

How serious is this? We do have released kernels out there with the
driver, you might want to consider a stable backport too.

Anyway, applied for 3.10.

--
Jens Axboe

2013-04-15 16:42:21

by Sam Bradshaw

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Subject: RE: [PATCH 2/2] mtip32xx: mtip32xx: Disable TRIM support


> On Fri, Apr 12 2013, Asai Thambi S P wrote:
> >
> > Temporarily disabling TRIM support until TRIM related issues
> > are addressed in the firmware.
>
> How serious is this? We do have released kernels out there with the
> driver, you might want to consider a stable backport too.

It's a performance issue, not data integrity. Since the ATA trim command
is non-queueable, IO traffic must halt while the trim is outstanding. A
filesystem that is actively trimming sectors is effectively duty cycling
the IO path on this part. We are working to shrink the trim command
latency while also investigating whether some sort of offline trim is more
appropriate.

Given the incremental endurance gain for trim on 34nm SLC vs the severe
throughput degradation under some workloads, it seemed prudent to disable
the feature.

If you think that warrants a stable backport, just let me or Asai know.

-Sam

2013-04-15 19:05:50

by Asai Thambi SP

[permalink] [raw]
Subject: Re: [PATCH 2/2] mtip32xx: mtip32xx: Disable TRIM support

On 4/14/2013 1:55 PM, Jens Axboe wrote:

> On Fri, Apr 12 2013, Asai Thambi S P wrote:
>>
>> Temporarily disabling TRIM support until TRIM related issues
>> are addressed in the firmware.
>
> How serious is this? We do have released kernels out there with the
> driver, you might want to consider a stable backport too.
>
> Anyway, applied for 3.10.
>

Added TRIM support in 3.9 merge window. If this trivial change could be
pushed, it would be good. Otherwise, I can backport to stable 3.9 when released.

--
regards,
asai