Hello Richard and others, > I get the use-case, but why is this only for mtdoops?
Powerpc's nvram module also stores oops messages and does so by adding an additional timestamp, as well (search for kmsg_dump_get_buffer() in arch/powerpc/kernel/nvram_64.c). This timestamp is the number of seconds since 1970 and stored as a 64 bit integer in the nvram header. Basically, the last kmesg timestamp is a few ms less than this additionally stored timestamp. Recording boottime would be more elegant, I guess. > IMHO this needs to go into generic code such that all kmsg dumpers can > benefit from it. This would be not that easy: #1 kmsg_dump_get_buffer(...size...) returns the most recent <size> bytes. Consecutive calls return older chunks. It would be natural to return the boottime as the first line, e.g. in the last call, but some clients such as mtdoops call kmsg_dump_get_buffer() only once. The returned buffer may be complete including boottime, or not. #2 consistency with other clients: nvram_64.c has the same requirement of storing a kind of wall-time but does it in a completely different way: no readable ascii text timestamp preprended to the kmsg buffer but a 64 bit timestamp in its header. Note, I don't think we should make mtdoops behave like nvram_64.c by storing the timestamp as a 64 bit integer (in its header) b/c most people do a cat or string of the mtd device /dev/mtdX and a 64 bit integer would just read as garbage. I hope we can have separate implementations for recording additional timestamps. Later, I'll send a patch with stylistic changes unless we completely disagree on how to move forward. Stefan
