Feedback on benchmarking results of SDHCI and MMCCAM driver

Udit agarwal dev.madaari at
Mon May 14 21:51:02 UTC 2018

On Tue, May 15, 2018 at 3:11 AM, Peter Jeremy <peter at> wrote:

> On 2018-May-15 02:48:43 +0530, Udit agarwal <dev.madaari at> wrote:
> >I have conducted several sd card benchmarking tests on FreeBSD 11.1, with
> >both SDHCI and the newly incorporated MMCCAM driver to compare their
> >performance under different conditions.
> Some questions:
> 1) How reproduceable are the results?  Have you performed the test
> multiple times
> to check for variance?
Yes, i have carried these tests multiple time and the results are pretty
consistent upto 0.1MBPS.

> 2) How did you prepare the SD card prior to each write test?  Flash write
> tests
> are extremely sensitive to hidden move/rewrite and erase cycles performed
> by the
> flash translation layer.
Before each test, I freshly recreated the filesystem to remove any trace of
the previous tests. Moreover, I have mounted/unmounted the device  to purge
any data in the cache.

> 3) Have you tried different SD cards from different manufacturers to see
> if the
> drivers happen to interact well or badly with the specific flash
> implementation.
No, currently i havn't experimented with different sd cards. True, it would
be interesting to figure out the interaction of the driver with different
flash implementations. I'll perform these tests ASAP.


> --
> Peter Jeremy

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