On Wed, 23 Jan 2013 14:05:25 +0800, bill4carson said:
Hmmm, all the boot messages are routed into a buffer it first printed into console, here there is no delay, possible tick timer are not setup yet. But when it does get printed into the console, this process could be interrupted by other action as well, that's where you see a 2sec delay.
Unlikely, unless Sandeep is running an actual serial console at a very low speed (which *can* cause fun on large NUMA machines that spew lots of messages). I'm pretty convinced that Sandeep is actually seeing a 2 second delay somewhere near mm_init that isn't reflected in the timestamps because mm_init runs before the clocks are set up. Of course, it may not be mm_init *itself* that's causing the delay - all we *really* know is it's somewhere between a printk in mm_init and the previous printk - there may be something *else* in between that's the actual time sink. Sandeep - I admit not having tried it, but can you see if booting with 'initcall_debug' narrows down where your problem is? If the initcall stuff is running early enough (I'm not sure when it starts relative to mm_init), you'll get a message from each initcall as it is entered end exited. With any luck, that will help narrow down exactly where your problem is.