#185: Need better SPI FLASH recovery procedure -------------------------------+-------------------------------------------- Reporter: [EMAIL PROTECTED] | Owner: [EMAIL PROTECTED] Type: task | Status: new Priority: high | Milestone: BTest-1 Component: linuxbios | Resolution: Keywords: | -------------------------------+-------------------------------------------- Comment (by [EMAIL PROTECTED]):
I now have a version of the recovery program that runs under Linux. Write performance is pretty good - reprogramming the whole thing takes 3+ minutes as with the standalone version. But read/verify performance sucks. It takes 2.5x longer than it should - 17 minutes instead of 7. The problem appears to be that reading a character from the serial driver causes a scheduling event, so the program doesn't wake up until the next 1 millisecond boundary. So instead of being able to read 2500 bytes per second (115200 baud is about 10K characters/sec, and each FLASH read moves 4 bytes over the serial line - 3 out and 1 in), you only get to read 1000 bytes per second. I don't think that the kernel I'm using has the fast scheduling patch... -- Ticket URL: <http://dev.laptop.org/ticket/185#comment:2> One Laptop Per Child <http://laptop.org/> _______________________________________________ Devel mailing list Devel@laptop.org http://mailman.laptop.org/mailman/listinfo/devel