리눅스 커널 인자 console 과 부팅시간

115k의 경우 미세하게 차이가 나지만...

라즈베리 파이 2라서 이정도 인데..

더 사양이 낮은걸로 가면 어떻게 되려나? 간격이 좁혀지려나? 궁금해지네..

나중에 PC에서도 해봐야겠다.

(빠르게 처리하고 출력이 느려서 발목잡히는거라면..

성능이 느린 녀석일수록 낮은 baud rate에서도 느려지지 않을 가능성이 높아 보이네..)

결론 : 시리얼 콘솔로 출력을 안하는게 미세하게라도 부팅을 빠르게 해준다.

       단, 느리면 미친듯이 느려짐(ex 2400bps)

시리얼 콘솔 OFF

$ cat /boot/cmdline.txt dwc_otg.lpm_enable=0 console=tty1 root=/dev/mmcblk0p2 rootfstype=ext4 elevator=deadline rootwait [    5.538787] i2c /dev entries driver [    8.942949] random: dd urandom read with 125 bits of entropy available [    9.218847] random: nonblocking pool is initialized [    9.239318] smsc95xx 1-1.1:1.0 eth0: hardware isn't capable of remote wakeup [   10.899741] smsc95xx 1-1.1:1.0 eth0: link up, 100Mbps, full-duplex, lpa 0xC5E1 [   14.062018] cfg80211: Calling CRDA to update world regulatory domain [   14.508474] Adding 102396k swap on /var/swap.  Priority:-1 extents:2 across:2134012k SSFS [   17.215920] cfg80211: Calling CRDA to update world regulatory domain

시리얼 콘솔 115k

$ cat /boot/cmdline.txt dwc_otg.lpm_enable=0 console=tty1 console=ttyAMA0,115200 root=/dev/mmcblk0p2 rootfstype=ext4 elevator=deadline rootwait [    6.610517] i2c /dev entries driver [    8.755376] random: nonblocking pool is initialized [   10.337207] smsc95xx 1-1.1:1.0 eth0: hardware isn't capable of remote wakeup [   11.845371] smsc95xx 1-1.1:1.0 eth0: link up, 100Mbps, full-duplex, lpa 0xC5E1 [   15.171890] cfg80211: Calling CRDA to update world regulatory domain [   15.575988] Adding 102396k swap on /var/swap.  Priority:-1 extents:2 across:2134012k SSFS [   18.323100] cfg80211: Calling CRDA to update world regulatory domain

시리얼 콘솔 2.4k

$ cat /boot/cmdline.txt dwc_otg.lpm_enable=0 console=tty1 console=ttyAMA0,2400 root=/dev/mmcblk0p2 rootfstype=ext4 elevator=deadline rootwait [   65.375014] i2c /dev entries driver [   69.878454] smsc95xx 1-1.1:1.0 eth0: hardware isn't capable of remote wakeup [   71.466722] smsc95xx 1-1.1:1.0 eth0: link up, 100Mbps, full-duplex, lpa 0xC5E1 [   74.321086] cfg80211: Calling CRDA to update world regulatory domain [   75.156305] Adding 102396k swap on /var/swap.  Priority:-1 extents:2 across:2134012k SSFS [   77.474999] cfg80211: Calling CRDA to update world regulatory domain

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시리얼 초기화에 시간이 이상하리 만치 오래 걸리고

확실히 메시지 출력에 시간소요 되는게 다르다.

115k - 0.004278초

[    0.696002] console [ttyAMA0] enabled

[    0.700280] bcm2835-mbox 3f00b880.mailbox: mailbox enabled

2.4k - 0.175674 초

[   24.166507] console [ttyAMA0] enabled

[   24.342181] bcm2835-mbox 3f00b880.mailbox: mailbox enabled

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2015.09.15

quiet 주면 로그가 출력이 거의 안되니까

부팅 시간에 영향을 거의 주지 않는다.

유의미한 부팅시간 차이는 없는 듯

no quiet / no console

$ cat /boot/cmdline.txt dwc_otg.lpm_enable=0 console=tty1 root=/dev/mmcblk0p2 rootfstype=ext4 elevator=deadline rootwait $ dmesg [    1.873744] smsc95xx v1.0.4 [    1.941273] smsc95xx 1-1.1:1.0 eth0: register 'smsc95xx' at usb-3f980000.usb-1.1, smsc95xx USB 2.0 Ethernet, b8:27:eb:7c:e2:4e [    2.158823] udevd[175]: starting version 175 [    4.436091] EXT4-fs (mmcblk0p2): re-mounted. Opts: (null) [    4.657410] EXT4-fs (mmcblk0p2): re-mounted. Opts: (null) [    5.213253] fuse init (API version 7.23) [    8.630851] random: dd urandom read with 121 bits of entropy available [    9.128626] smsc95xx 1-1.1:1.0 eth0: hardware isn't capable of remote wakeup [    9.533223] random: nonblocking pool is initialized [   10.676478] smsc95xx 1-1.1:1.0 eth0: link up, 100Mbps, full-duplex, lpa 0xC5E1 [   11.380752] Adding 102396k swap on /var/swap.  Priority:-1 extents:2 across:2134012k SSFS

quiet / 2400bps

$ cat /boot/cmdline.txt dwc_otg.lpm_enable=0 console=tty1 console=ttyAMA0,2400 root=/dev/mmcblk0p2 rootfstype=ext4 elevator=deadline rootwait quiet $ dmesg [    1.787155] smsc95xx v1.0.4 [    1.849754] smsc95xx 1-1.1:1.0 eth0: register 'smsc95xx' at usb-3f980000.usb-1.1, smsc95xx USB 2.0 Ethernet, b8:27:eb:7c:e2:4e [    2.159625] udevd[175]: starting version 175 [    4.475902] EXT4-fs (mmcblk0p2): re-mounted. Opts: (null) [    4.687585] EXT4-fs (mmcblk0p2): re-mounted. Opts: (null) [    5.243639] fuse init (API version 7.23) [    8.657857] random: dd urandom read with 122 bits of entropy available [    9.236423] smsc95xx 1-1.1:1.0 eth0: hardware isn't capable of remote wakeup [    9.285362] random: nonblocking pool is initialized [   10.784245] smsc95xx 1-1.1:1.0 eth0: link up, 100Mbps, full-duplex, lpa 0xC5E1 [   11.661120] Adding 102396k swap on /var/swap.  Priority:-1 extents:2 across:2134012k SSFS

quiet / 115k

$ cat /boot/cmdline.txt dwc_otg.lpm_enable=0 console=tty1 console=ttyAMA0,115200 root=/dev/mmcblk0p2 rootfstype=ext4 elevator=deadline rootwait quiet $ dmesg [    1.787064] smsc95xx v1.0.4 [    1.848037] smsc95xx 1-1.1:1.0 eth0: register 'smsc95xx' at usb-3f980000.usb-1.1, smsc95xx USB 2.0 Ethernet, b8:27:eb:7c:e2:4e [    2.083949] udevd[175]: starting version 175 [    4.375384] EXT4-fs (mmcblk0p2): re-mounted. Opts: (null) [    4.588231] EXT4-fs (mmcblk0p2): re-mounted. Opts: (null) [    5.138807] fuse init (API version 7.23) [    8.506983] random: dd urandom read with 123 bits of entropy available [    9.087136] smsc95xx 1-1.1:1.0 eth0: hardware isn't capable of remote wakeup [    9.132055] random: nonblocking pool is initialized [   10.595072] smsc95xx 1-1.1:1.0 eth0: link up, 100Mbps, full-duplex, lpa 0xC5E1 [   11.272396] Adding 102396k swap on /var/swap.  Priority:-1 extents:2 across:2134012k SSFS

[링크 : http://elinux.org/Disable_Console]

[링크 : https://www.kernel.org/doc/Documentation/kernel-parameters.txt]

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2015.09.16

라즈베리 B에서 테스트

2400bps로 설정하면 라즈베리 B나 2B나 부팅시간이 거의 동일해진다 ㄷㄷ

# cat /flash/cmdline.txt

boot=/dev/mmcblk0p1 disk=/dev/mmcblk0p2 quiet

[    6.260069] lirc_rpi: auto-detected active low receiver on GPIO pin 18

[    6.260446] lirc_rpi lirc_rpi.0: lirc_dev: driver lirc_rpi registered at minor = 0

[    6.260465] lirc_rpi: driver registered!

[    9.116106] Console: switching to colour dummy device 80x30

[   10.033464] pcm512x 1-004d: Failed to reset device: -5

[   10.033606] pcm512x: probe of 1-004d failed with error -5

[   10.038823] pcm512x 1-004c: Failed to reset device: -5

[   10.038972] pcm512x: probe of 1-004c failed with error -5

[   11.996185] smsc95xx 1-1.1:1.0 eth0: hardware isn't capable of remote wakeup

[   11.996923] IPv6: ADDRCONF(NETDEV_UP): eth0: link is not ready

[   13.503507] input: lircd as /devices/virtual/input/input0

[   13.513621] smsc95xx 1-1.1:1.0 eth0: link up, 100Mbps, full-duplex, lpa 0xCDE1

[   13.543861] IPv6: ADDRCONF(NETDEV_CHANGE): eth0: link becomes ready

# cat /flash/cmdline.txt

boot=/dev/mmcblk0p1 disk=/dev/mmcblk0p2 console=ttyAMA0,115200

[    7.583641] lirc_rpi: auto-detected active low receiver on GPIO pin 18

[    7.584050] lirc_rpi lirc_rpi.0: lirc_dev: driver lirc_rpi registered at minor = 0

[    7.584073] lirc_rpi: driver registered!

[    7.590570] systemd[1]: Reached target Local File Systems.

[    7.590980] systemd[1]: Started Rebuild Journal Catalog.

[    7.607263] systemd[1]: Started Load Kernel Modules.

[    7.673956] systemd[1]: Started Journal Service.

[    7.835377] systemd-journald[149]: Received request to flush runtime journal from PID 1

[   11.254985] Console: switching to colour dummy device 80x30

[   12.137394] pcm512x 1-004d: Failed to reset device: -5

[   12.137547] pcm512x: probe of 1-004d failed with error -5

[   12.142543] pcm512x 1-004c: Failed to reset device: -5

[   12.142698] pcm512x: probe of 1-004c failed with error -5

[   14.273315] smsc95xx 1-1.1:1.0 eth0: hardware isn't capable of remote wakeup

[   14.276243] IPv6: ADDRCONF(NETDEV_UP): eth0: link is not ready

[   15.827031] smsc95xx 1-1.1:1.0 eth0: link up, 100Mbps, full-duplex, lpa 0xCDE1

[   15.861468] IPv6: ADDRCONF(NETDEV_CHANGE): eth0: link becomes ready

[   15.930351] input: lircd as /devices/virtual/input/input0

# cat /flash/cmdline.txt

boot=/dev/mmcblk0p1 disk=/dev/mmcblk0p2 console=ttyAMA0,2400

[   59.096555] lirc_rpi: auto-detected active low receiver on GPIO pin 18

[   59.096935] lirc_rpi lirc_rpi.0: lirc_dev: driver lirc_rpi registered at minor = 0

[   59.096958] lirc_rpi: driver registered!

[   59.253490] systemd[1]: Mounted Temporary Directory.

[   59.530181] systemd[1]: Started Remount Root and Kernel File Systems.

[   59.910190] systemd[1]: Started Create list of required static device nodes for the current kernel.

[   60.106840] systemd[1]: Started Setup machine-id.

[   60.323515] systemd[1]: Started Set ondemand threshold.

[   60.500170] systemd[1]: Started Show Version.

[   60.716824] systemd[1]: Started Load Kernel Modules.

[   60.950148] systemd[1]: Started Kodi config dir rebrand.

[   61.146860] systemd[1]: Started Mounting swapfile.

[   61.376843] systemd[1]: Started udev Coldplug all Devices.

[   61.848866] systemd[1]: Starting Swap.

[   62.016818] systemd[1]: Reached target Swap.

[   62.017203] systemd[1]: Mounted FUSE Control File System.

[   62.018077] systemd[1]: Mounted Configuration File System.

[   62.018331] systemd[1]: Starting Apply Kernel Variables...

[   62.213534] systemd[1]: Starting Journal Service...

[   62.377729] systemd[1]: Starting Create Static Device Nodes in /dev...

[   62.620386] systemd[1]: Starting Setup Timezone data...

[   62.804543] systemd[1]: Started Debug /var/log relink.

[   63.003508] systemd[1]: Started Journal Service.

[   64.752792] systemd-journald[160]: Received request to flush runtime journal from PID 1

[   69.797632] pcm512x 1-004d: Failed to reset device: -5

[   69.797788] pcm512x: probe of 1-004d failed with error -5

[   69.802172] pcm512x 1-004c: Failed to reset device: -5

[   69.802323] pcm512x: probe of 1-004c failed with error -5

[   71.876799] Console: switching to colour dummy device 80x30

[   75.422833] smsc95xx 1-1.1:1.0 eth0: hardware isn't capable of remote wakeup

[   75.425714] IPv6: ADDRCONF(NETDEV_UP): eth0: link is not ready

[   76.986887] smsc95xx 1-1.1:1.0 eth0: link up, 100Mbps, full-duplex, lpa 0xCDE1

[   76.995598] IPv6: ADDRCONF(NETDEV_CHANGE): eth0: link becomes ready

[   78.083255] input: lircd as /devices/virtual/input/input0