Hello
I have got some interesting numbers when benchmarking loading of large jpeg
files.
Jpeg size = 7.13 MB
Loading jpeg (Tungsten/t, MMC card):
- from the card 28 secs
- from RAM 8 secs
The same card used in Nokia 3650:
Loading the same jpeg takes 18 secs. (The same loader used.)
Copying the same jpeg file on T/t:
card -> card = 85 secs
card -> RAM = 21 secs
Some technical details:
Jpeg loader uses 4K buffer when reading from the card. Previous tests showed
that this is a quite good compromise - larger buffers bring negligible
gains.
File copy is realized in 16K blocks. Also, a few sporadic tests indicated
that larger buffer does not bring too much.
Nokia 3650 is ARM 9, 104 MHz.
T/t is OMAP 1510 with 144 MHz.
Processors are not exactly my area, but I would say that T/t should be a bit
faster. (For the jpeg loading: Work done in M68K mode is negligible
compared to the work done in the ARM mode.)
We could not benchmark RAM loading on Nokia (because the jpeg was too big),
but this was not my primary interest. Anyway, in case that the eventual
discussion would require it, I can do that later.
For me the basic question is: Why the card reading is so slow on T/t, or
what can be done to speed it up?
Arguments of the kind that Palm must be prepared to the drive removal may
sound logically when comparing to Nokia (where the card exchange can be done
only in the switched off state), but I am to 90% sure that we would get
similar differences between Palm and PocketPC (they are both in the same
situation).
Can anybody give me some explanation?
Regards,
Jan Slodicka
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