On Tue, 22 Jan 2013 11:32:19 -0800, sandeep kumar said: > as you rightly mentioned,cat /proc/kmsg is showing the time stamps, > according to that it is 0ms only. > But when you see the same with UART there is 2sec delay in showing the next > log. i caught this while i m observing the UART logs with > "Terminaliranicca". Oh, I could believe there's 2 seconds of time used up there that doesn't show in kernel timestamps because the timers aren't started yet. > Since i m early in the mm_init, i cant use watchdog to detect it, hrtimers > i cant use..i am really thinking how to analyse this delay.. Time for some lateral thinking.. :) Can you give us some specs on the hardware (in particular, the CPU type/speed and how much RAM is installed)? 2 seconds on a 2Ghz CPU is about 4 billion cycles. Also, are you adding any code into the mm_init path? If so, what exactly are you doing? I wonder how early the kernel tracing and profiling stuff is enabled. It may be possible to boot a kernel that has function-call tracing enabled, which would not have timing info, but if you see a function that's being called 500K times that should only be called a dozen times, that's probably your problem :) You'd probably want it with 'init=/bin/bash' and dump the stuff, as running to multiuser will almost certainly roll the buffers and lose the info).
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