Thanks for the replies. I didn't realize that the MMC module was operating in 1-bit mode inside U-boot. I'll concentrate on looking at that. Has anybody done any work to try and get 4-bit mode working for OMAP3 in U-boot?
Thanks, Chris On Thu, Oct 7, 2010 at 1:04 PM, Wolfgang Denk <w...@denx.de> wrote: > Dear chris c, > > In message > <aanlkti=usueyf4yuuvwrrlu80bmrfprf+btheix2b...@mail.gmail.com<usueyf4yuuvwrrlu80bmrfprf%2bbtheix2b...@mail.gmail.com>> > you wrote: > > > > I was comparing time just by timing it manually. How did you instrument > > u-boot to display the time? > > That's no instrumentation of U-Boot, but just timestamping the output > on the serial console. See for example > ftp://ftp.denx.de/pub/tools/time_log > > > As for the small versus large file, I did the same test for 1MB of data > > using nand read and saw a x4 performance advantage. I also did a test on > > mmc with 100 MB file and saw no performance increase. Looks like file > size > > doesn't matter. > > > > So does that mean that MMC file loading will not benefit from dcache > > enabled? Can anybody explain this? > > It depends on where the time is actually spent. If you have a slow > (say, bit-banging) MMC driver and a low-performance CPU then the > transfer from MMC might simply not depend as much on caches. It is > wrong to check just a simple use case. Try a number of different > operations, like umcompressing a large image in RAM or from NOR to > RAM, or downloading over the net, or ... > > Best regards, > > Wolfgang Denk > > -- > DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel > HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany > Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: w...@denx.de > "Remember, Information is not knowledge; Knowledge is not Wisdom; > Wisdom is not truth; Truth is not beauty; Beauty is not love; Love is > not music; Music is the best." - Frank Zappa >
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