<div dir="ltr">Hi Valdis,<div style>Device specs: CPU: 1.7Ghz & RAM: 2GB.</div><div style>We are not adding any code in the mm_init, All we do is reserve some memory during the boot time and rest of the memory around 1.45GB we configure it as HIGHMEM.</div>
<div style><br></div><div style>Can you give me any info on how to do the profiling of the function calls during ealry booting in the kernel.</div><div style><br></div><div style>Thanks</div><div style>Sandeep</div></div>
<div class="gmail_extra"><br><br><div class="gmail_quote">On Tue, Jan 22, 2013 at 12:38 PM, <span dir="ltr"><<a href="mailto:Valdis.Kletnieks@vt.edu" target="_blank">Valdis.Kletnieks@vt.edu</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div class="im">On Tue, 22 Jan 2013 11:32:19 -0800, sandeep kumar said:<br>
<br>
> as you rightly mentioned,cat /proc/kmsg is showing the time stamps,<br>
> according to that it is 0ms only.<br>
> But when you see the same with UART there is 2sec delay in showing the next<br>
> log. i caught this while i m observing the UART logs with<br>
> "Terminaliranicca".<br>
<br>
</div>Oh, I could believe there's 2 seconds of time used up there that doesn't<br>
show in kernel timestamps because the timers aren't started yet.<br>
<div class="im"><br>
> Since i m early in the mm_init, i cant use watchdog to detect it, hrtimers<br>
> i cant use..i am really thinking how to analyse this delay..<br>
<br>
</div>Time for some lateral thinking.. :)<br>
<br>
Can you give us some specs on the hardware (in particular, the CPU type/speed<br>
and how much RAM is installed)? 2 seconds on a 2Ghz CPU is about 4 billion<br>
cycles.<br>
<br>
Also, are you adding any code into the mm_init path? If so, what exactly<br>
are you doing?<br>
<br>
I wonder how early the kernel tracing and profiling stuff is enabled. It may<br>
be possible to boot a kernel that has function-call tracing enabled, which<br>
would not have timing info, but if you see a function that's being called 500K<br>
times that should only be called a dozen times, that's probably your problem :)<br>
You'd probably want it with 'init=/bin/bash' and dump the stuff, as running to<br>
multiuser will almost certainly roll the buffers and lose the info).<br>
<br>
</blockquote></div><br><br clear="all"><div><br></div>-- <br>With regards,<br>Sandeep Kumar Anantapalli,<br>
</div>