How do I install 299 on the main flash without an autoreinstallation image?
owen On Sat, 2007-03-10 at 12:46 -0500, Jim Gettys wrote: > On Sat, 2007-03-10 at 22:58 +0545, Bipin Gautam wrote: > > hello, > > I experimented with various block size for file I/O. I experimented > > with vfat and ext2 filesystem in the pen drive. > > Without specifications on the Pen drive, it's hard predict what would > happen. Write performance of file systems on flash depends on whether > the block size of the file system matches well the underlying flash > block size. > > > i also experimented > > with file write within nand storage; like > > > > date > > dd if=/dev/zero of=/testfile bs=6144 count=102400 > > date > > On the NAND flash: > > JFFS2 does data compression. > > If you are writing zeros into a file, the actual write will extremely > highly compressed, and so you are appending small writes to the log; to > rewrite blocks on the log, you have to read the blocks, and might > encounter errors. This can have significant performance consequences, > which I think are fixed in later builds. > > > > > > The maximum preformance of XO nand storage (alone) was ~1.8 mb/sec > > (jffs2) while the preformance of external usb drive is ~ 3-11 mb /sec > > (at various block size) > > Please install build 299, rather than 239. There has been work on the > NAND driver to highly optimize the error correction path in the NAND > driver, which I believe was not in build 239, but IIRC, is in build 299. > > So if you had NAND with errors, the error correction path was a possible > source of CPU usage. I believe the error correction code is now 100 or > more times faster, courtesy of a community developer whose name slips my > mind. > > > > > > i thought 100% cpu use is because direct memory access(DMA) for disk > > I/O has some problems (or disabled). Also, running XO OS[1] in > > virtual machine inside Parallels Workstation 2.2 with host OS xp sp2 > > shows the same problem of 100% cpu use during disk i/o > > > > > > i cant give you a detailed stats. right now as my B2 OS is dead and > > i'm downloading the latest build. (maybe tomorrow... if you want to > > hear it) > > Please install build 299. > > > > > with regards, > > -bipin > > [1]olpc-redhat-stream-development-build-239-20070118_1416-devel_ext _______________________________________________ Devel mailing list [email protected] http://mailman.laptop.org/mailman/listinfo/devel
