Re: [PATCHv3 4/5] mtd: mxc_nand fixups

From: Ivo Clarysse
Date: Fri Jun 25 2010 - 10:46:52 EST

On Thu, Jun 24, 2010 at 9:27 AM, Sascha Hauer <s.hauer@xxxxxxxxxxxxxx> wrote:
> BTW I observed that at least on i.MX27 the latencies introduced by
> waiting for an interrupt cause a significant performance drop. The
> driver gets much faster when we just poll all the time. I don't know how
> this affects system performance otherwise, but it may be a possibility
> to drop interrupt support at least for i.MX21. I have no idea how long
> the longest possible time we'd have to poll is though.

I'm noticing the same thing on i.MX21: when using interrupts,
"Scanning device for bad blocks" takes 982 (!) seconds. When always
using polling, the same scan takes 'only' 500 seconds.

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