On Thu, 2014-03-27 at 23:05 +0800, Axel Lin wrote:
>
> Refactor to use default implementation of transfer_one_message() which
> provides
> standard handling of delays and chip select management.
>
> Signed-off-by: Axel Lin <[email protected]>
> ---
> Hi Gerhard and Anatolij,
> I don't have this h/w. I'd appreciate if you can test this patch.
>
> Thanks,
> Axel
although the change appears to work (LCD and SPI flash remain
operational), it dramatically reduces throughput (increase of
transfer time from 10 to 150 seconds)
before:
root@ac14xx:~# uname -srm
Linux 3.14.0-rc8-00011-gf217c44ebd41 ppc
root@ac14xx:~# time wc /dev/mtd6
23 68 16777216 /dev/mtd6
real 0m 9.87s
user 0m 0.68s
sys 0m 0.17s
root@ac14xx:~# time dd if=/dev/mtd6 of=/dev/null bs=1024
16384+0 records in
16384+0 records out
real 0m 10.11s
user 0m 0.04s
sys 0m 0.55s
after:
root@ac14xx:~# uname -srm
Linux 3.14.0-rc8-00012-gc47c572ff209 ppc
root@ac14xx:~# time wc /dev/mtd6
23 68 16777216 /dev/mtd6
real 2m 34.97s
user 0m 0.00s
sys 0m 0.94s
root@ac14xx:~# time dd if=/dev/mtd6 of=/dev/null bs=1024
16384+0 records in
16384+0 records out
real 3m 17.11s
user 0m 0.00s
sys 0m 0.91s
can you reproduce this on other hardware? the change looks
innocent, and the core routine looks straight forward -- is some
expensive diagnostics enabled ATM during transition to common
logic?
virtually yours
Gerhard Sittig
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