When my kernel boots, apart from the useful important information, it prints lots of debugging info, such as
....
kernel: [0.00000] BIOS-e820: [mem 0x0000000000000000-0x000000000009d3ff] usable
kernel: [0.00000] BIOS-e820: [mem 0x000000000009d400-0x000000000009ffff] reserved
kernel: [0.00000] BIOS-e820: [mem 0x00000000000e0000-0x00000000000fffff] reserved
...
kernel: [0.00000] MTRR variable ranges enabled:
kernel: [0.00000] 0 base 0000000000 mask 7E00000000 write-back
...
kernel: [0.00000] init_memory_mapping: [mem 0x00100000-0xcf414fff]
kernel: [0.00000] [mem 0x00100000-0x001fffff] page 4k
kernel: [0.00000] [mem 0x00200000-0xcf3fffff] page 2M
kernel: [0.00000] [mem 0xcf400000-0xcf414fff] page 4k
....
kernel: [0.00000] ACPI: XSDT 0xD8FEB088 0008C (v01 DELL CBX3 01072009 AMI 10013)
kernel: [0.00000] ACPI: FACP 0xD8FFC9F8 0010C (v05 DELL CBX3 01072009 AMI 10013)
....
kernel: [0.00000] Early memory node ranges
kernel: [0.00000] node 0: [mem 0x00001000-0x0009cfff]
kernel: [0.00000] node 0: [mem 0x00100000-0xcf414fff]
kernel: [0.00000] node 0: [mem 0xcf41c000-0xcfdfcfff]
....
kernel: [0.00000] ACPI: Local APIC address 0xfee00000
kernel: [0.00000] ACPI: LAPIC (acpi_id[0x01] lapic_id[0x00] enabled)
kernel: [0.00000] ACPI: LAPIC (acpi_id[0x02] lapic_id[0x02] enabled)
and much much more.
I don't see how this can be useful to anybody other than a kernel developer/debugger.
I have found, that I can get rid of these by using loglevel=5
as boot parameter. The debugging logs are no longer printed on the terminal, but they are still in dmesg
and in syslog
.
Is it possible to decrease the boot log verbosity globally, so that dmesg
and syslog
are not flooded by this useless information ?
I am using self compiled kernel 3.18
ACEPTED SOLUTION
Turns out, putting following lines to /etc/rsyslog.conf
solved the problem for me:
kern.debug /dev/null
& ~
Best Answer
For syslog You can add following line to
/etc/syslog.conf
:It will discard kernel .info and .debug messages ( which are discarded with loglevel=5 )
Also,
dmesg
can be used with option-n
to show messages with certain loglevel.