That might become moot if we switch from zlib to LZO for JFFS2, as has been discussed.
NoiseEHC wrote: > This message is primarily written for Bernardo Innocenti but everybody > with relevant knowledge is welcomed to give some insight. > > I have decided two months ago that will write an asm implementation for > zlib inflate (decompression) since Mitch Bradley said that the read > speed is 3MB/sec which is dominated by the decompression code. > http://lists.laptop.org/pipermail/devel/2007-November/007527.html > > > Since then I went through the pain of installing linux in VirtualPC, > compiling the code in linux and ended up with a kernel module which can > test zlib code finally (took a month of my spare time, if I would have > known this in advance I would not have started...). Now I understand the > zlib code but need some info before acting on wrong assumptions: > > 1. Did anybody profile the kernel while reading files? Last thing I red > on this list is that the profiler does not work on the XO in kernel > mode. Did anybody fix that? > 2. How does the file reading work? As I imagine the flash is read by DMA > and the resulting data is uncompressed to a buffer. Is it correct?. Is > the decompressed data gets copied to the target location or does it gets > decompressed to their final place? If it is copied, did somebody profile > how much time it takes? These questions are important to know how much > L2 cache is trashed in the process and which data needs prefetching. > 3. How long is the average data length which jffs2 uses for calling inflate? > 4. What is the average size of the length/distance code table? > 4. Bernardo, as I imagine you are compiling kernels every day. If I send > you a "patch" (normally a rewritten inffast.c), would you test it on a > real XO machine, please? > > Thanks. > > _______________________________________________ > Devel mailing list > Devel@lists.laptop.org > http://lists.laptop.org/listinfo/devel > _______________________________________________ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel