On Wednesday 13 May 2009, Liu Yebo wrote:
> Hi,
> 
> I've been doing some testing with SD card writes on the our
> dm355 board.That looks that the performance is dismal, that
> is pretty poor. i was getting speeds of around 2-3MB/s for write.

Write performance can be gated by card performance; not all
cards can write very fast.  A more portable test is read
performance ... bad read performance indicates something you
have can fix fairly easily, and which would also affect write
performance (to the extent your card can write faster).

Current kernels get over 9 MB/sec reads on fast cards, with
no tweaking.  Older kernels may need to enable the MMC bounce
buffer option to get comparable throughput.  If your kernel
doesn't have a bounce buffer option, maybe you can upgrade.

 
> Now i have enable high speed SD support.

I don't recall ever seeing a kernel that supported that
but needed to somehow "enable" it.  It should just kick
in automatically when it sees an SDHC card.

- Dave

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