dtrace discuss - Dec 2008 - uptime : timestamp?

Hi all,
 can I get system uptime in sec through dtrace?

Cheers,
Alex
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This message posted from opensolaris.org

Alexander R. Eremin wrote:
> Hi all,
>  can I get system uptime in sec through dtrace?
if this is an exercise in and of itself, dtrace is probably not the easiest 
way to go :-)... having said that: the kernel variable lbolt counts the 
ticks since boot time. Divide that by the number of ticks per second (100, 
in most cases) ... you get the idea :-)

cheers
Michael
-- 
Michael Schuster     http://blogs.sun.com/recursion
Recursion, n.: see ''Recursion''

Thanks Michael,
I need to get uptime in anonymous tracing, after kernel booting - this is
problem.
I can get timestamps but these values in nanoseconds and looks like not right
for
uptime.

Cheers,
Alex
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This message posted from opensolaris.org

To put some ''D'' around Michael''s suggestion try
something like:

$ pfexec dtrace -qn ''fbt:genunix:ddi_get_lbolt:return { \
lbolt = args[1]; \
lboltsec = (lbolt / 100); \
days = (lboltsec / 86400); \
hours = (lboltsec / 3600) - (days * 24); \
minutes = (lboltsec / 60) - (days * 1440) - (hours * 60); \
seconds = (lboltsec % 60); \
printf("uptime %d days, %d hours, %d minutes, %d seconds\n", days,
hours, minutes, seconds); \
exit(0); \
}''
uptime 0 days, 6 hours, 29 minutes, 38 seconds

Note if your script is doing other things besides grabbing the lbolt you
don''t want to exit(0) so look to use the profile provider or put the
calculations & printf() statement somewhere else so it doesn''t get
called at high frequencies.

If you''d rather just print the lbolt and do some post-processing you
could use the trace() functionality within D to get the lbolt value:

$ pfexec dtrace -qn ''dtrace:::BEGIN { trace(`lbolt); exit(0);
}''
2539374


If all you want to do is execute ''uptime'' from within D look
at the system() function - Note you''ll need to be in destructive/write
mode for this.

$ pfexec dtrace -wqn ''dtrace:::BEGIN { system("uptime");
exit(0); }''
  4:27am  up   7:07,  3 users,  load average: 0.08, 0.08, 0.07


Would kstat work for you?

$ kstat -p unix:0:system_misc:lbolt
unix:0:system_misc:lbolt	2413045
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