> I am using a kernel retrieved from TI's site on Apr 20/08. I built the > kernel with the only change to the config being the inclusion of the > resizer driver. > > On Windows Vista, my 150x 2GB SD card gets a write speed of > 4 GB/s > over a 128 MB file.
It's hard to believe those numbers are correct. You're probably hitting the disk cache at 4GB/s with your 128MB file (and then not even that fast - there are probably gross rounding errors because the actual time was so small). It doesn't actually hit the SD card at this speed. The SD card speed can't be more than 25MB/s (4-bit interface * 50MHz clock), and it's even less than that due to SD being a high latency protocol. In reality, it's closer to 20MB/s if everything was running perfectly optimally. > On the embedded system my write speed is 135 kB/s - an unbelievable 3%!! Well, yes that is pretty poor. At least on the DM6446, the git kernel has a different driver with which I was getting speeds of around 2-3 MB/s for write, and a 5-6 MB/s on reads (at the 2.4.24 branch). > Has anyone looked at the SD driver and/or SD interface? I was not > planning on touching this driver, never mind having to rewrite big > chunks of it :( I don't know if anybody is using the git kernel on the DM355. But I'm willing to bet that it would be less effort to port git to DM355 than the SD driver to MV's 2.6.10. Cheers, Bernard. _______________________________________________ Davinci-linux-open-source mailing list [email protected] http://linux.davincidsp.com/mailman/listinfo/davinci-linux-open-source
