Am 02.08.2018 um 17:01 schrieb Bean Huo (beanhuo): >>> I am newbie on ext4, I tried the above method to disable readahead, echo >> 0 > /sys/block/<dev>/queue/read_ahead_kb >>> Then I read by 128kB chunk size, ext4 will read the file by 4KB chunk size >> each time. that means ext4 splits 128KB into 32 4KB to read. >>> That's not my expectation. >>> Do you know how to still keep and let ext4 read by 128KB in case of disable >> readahead? >>> Thanks. >>> >>> //bean huo >> I guess you're doing buffered IO, have you try to use direct IO? >> > Direct I/O is another case, it is true that will bypass readahead. > But I want to disable readahead with page cache. don't get me wrong but when you state "I am newbie on ext4" this all sounds like "having solution, seeking for problem"
