printk - What does the numbers at the beginning of prink() mean? -

if use prink() print kernel message , read in console, looks this:

<6>[ 2809.666228] amp_enable: amp enable bypass(2)   <6>[ 2809.666747] amp_enable: amp_en set 0   <3>[ 2810.084296] init: untracked pid 4196 exited   <3>[ 2810.873706] init: untracked pid 4817 exited   <6>[ 2810.933923] msm_ta_detect_work: usb exit ta detection - frindex   <6>[ 2817.483839] amp_enable: amp_en set 1   <6>[ 2823.084022] adjust_soc: ibat_ua = -114500, vbat_uv = 4296066, soc = 95, batt_temp=302   <6>[ 2823.669799] slim_cl: skip reconfig sequence   <6>[ 2823.685578] amp_enable: amp enable bypass(2)   <6>[ 2823.686372] amp_enable: amp_en set 0   

what number @ beginning of each line mean? kind of time stamp? how interpret it?

as ng mentioned, <3> , <6> log levels <3> kern_err , <6> kern_info.

here's list picked http://tuxthink.blogspot.com/2012/07/printk-and-console-log-level.html.

0 kern_emerg 1 kern_alert 2 kern_crit 3 kern_err 4 kern_warning 5 kern_notice 6 kern_info 7 kern_debug 

the next number appears time in seconds since system boot. did system boot ~50 minutes ago when saw these messages? timestamps can track how long task took. example, amp_enable: amp enable bypass(2) took 0.519ms complete. first entry fourth entry, took 1.207478s.

<6>[ 2809.666228] amp_enable: amp enable bypass(2)   <6>[ 2809.666747] amp_enable: amp_en set 0   <3>[ 2810.084296] init: untracked pid 4196 exited   <3>[ 2810.873706] init: untracked pid 4817 exited  

i learned visiting http://elinux.org/printk_times_sample1.