In message <47AA08E7.5000801@xxxxxxx> you wrote: > > > I actually think the kernel should operate with block sizes > > like this and not wth 4 kiB blocks. It is the readahead and the elevator > > algorithms that save us from randomly reading 4 kb a time. > > > > > Exactly, and nothing save a R-A-RW cycle if the write is a partial chunk. Indeed kernel page size is an important factor in such optimizations. But you have to keep in mind that this is mostly efficient for (very) large strictly sequential I/O operations only - actual file system traffic may be *very* different. We implemented the option to select kernel page sizes of 4, 16, 64 and 256 kB for some PowerPC systems (440SPe, to be precise). A nice graphics of the effect can be found here: https://www.amcc.com/MyAMCC/retrieveDocument/PowerPC/440SPe/RAIDinLinux_PB_0529a.pdf 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: wd@xxxxxxx You got to learn three things. What's real, what's not real, and what's the difference." - Terry Pratchett, _Witches Abroad_ - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
