ubuntu 16.04 booting is taking more than 1.5 minute

If you run:

dmesg | less

You can see the boot, the number on the left is the number of seconds. Look for large gaps in time. Do you see any?

yes...there are a few delays taking more than 20s of time also......

[ 24.082155] Bluetooth: hci0: BCM: chip id 70
[ 24.098159] Bluetooth: hci0: BCM43142A
[ 24.098164] Bluetooth: hci0: BCM (001.001.011) build 0000
[ 27.456142] audit: type=1400 audit(1469154766.135:2): apparmor="STATUS" operation="profile_load" profile="unconfined" name="/usr/bin/ubuntu-core-launcher" pid=2598 comm="apparmor_parser"
[ 27.457299] audit: type=1400 audit(1469154766.135:3): apparmor="STATUS" operation="profile_load" profile="unconfined" name="/sbin/dhclient" pid=2595 comm="apparmor_parser"
[ 27.457307] audit: type=1400 audit(1469154766.135:4): apparmor="STATUS" operation="profile_load" profile="unconfined" name="/usr/lib/NetworkManager/nm-dhcp-client.action" pid=2595 comm="apparmor_parser"
[ 27.457314] audit: type=1400 audit(1469154766.135:5): apparmor="STATUS" operation="profile_load" profile="unconfined" name="/usr/lib/NetworkManager/nm-dhcp-helper" pid=2595 comm="apparmor_parser"
[ 27.457319] audit: type=1400 audit(1469154766.135:6): apparmor="STATUS" operation="profile_load" profile="unconfined" name="/usr/lib/connman/scripts/dhclient-script" pid=2595 comm="apparmor_parser"
[ 27.457971] audit: type=1400 audit(1469154766.135:7): apparmor="STATUS" operation="profile_load" profile="unconfined" name="/usr/lib/lightdm/lightdm-guest-session" pid=2594 comm="apparmor_parser"
[ 27.457978] audit: type=1400 audit(1469154766.135:8): apparmor="STATUS" operation="profile_load" profile="unconfined" name="/usr/lib/lightdm/lightdm-guest-session//chromium" pid=2594 comm="apparmor_parser"
[ 27.459034] audit: type=1400 audit(1469154766.139:9): apparmor="STATUS" operation="profile_load" profile="unconfined" name="/usr/sbin/cups-browsed" pid=2601 comm="apparmor_parser"
[ 27.461112] audit: type=1400 audit(1469154766.139:10): apparmor="STATUS" operation="profile_load" profile="unconfined" name="/usr/lib/cups/backend/cups-pdf" pid=2602 comm="apparmor_parser"
[ 27.461128] audit: type=1400 audit(1469154766.139:11): apparmor="STATUS" operation="profile_load" profile="unconfined" name="/usr/sbin/cupsd" pid=2602 comm="apparmor_parser"
[ 28.519699] bluetooth hci0: Direct firmware load for brcm/BCM.hcd failed with error -2
[ 28.519705] Bluetooth: hci0: BCM: Patch brcm/BCM.hcd not found
[ 30.164768] cgroup: new mount options do not match the existing superblock, will be ignored
[ 30.809243] Bluetooth: BNEP (Ethernet Emulation) ver 1.3
[ 30.809246] Bluetooth: BNEP filters: protocol multicast
[ 30.809249] Bluetooth: BNEP socket layer initialized
[ 34.437680] IPv6: ADDRCONF(NETDEV_UP): wlan0: link is not ready
[ 34.440218] IPv6: ADDRCONF(NETDEV_UP): eth0: link is not ready
[ 35.100000] r8169 0000:07:00.0 eth0: link down
[ 35.100056] IPv6: ADDRCONF(NETDEV_UP): eth0: link is not ready
[ 36.430493] cfg80211: Regulatory domain changed to country: IN
[ 36.430496] cfg80211: DFS Master region: JP
[ 36.430497] cfg80211: (start_freq - end_freq @ bandwidth), (max_antenna_gain, max_eirp), (dfs_cac_time)
[ 36.430499] cfg80211: (2402000 KHz - 2482000 KHz @ 40000 KHz), (N/A, 2000 mBm), (N/A)
[ 36.430500] cfg80211: (5170000 KHz - 5250000 KHz @ 80000 KHz, 160000 KHz AUTO), (N/A, 2000 mBm), (N/A)
[ 36.430502] cfg80211: (5250000 KHz - 5330000 KHz @ 80000 KHz, 160000 KHz AUTO), (N/A, 2000 mBm), (0 s)
[ 36.430503] cfg80211: (5735000 KHz - 5835000 KHz @ 80000 KHz), (N/A, 2000 mBm), (N/A)
(END)

The output above indicates that initializing the Bluetooth system takes quite some time, and also ipv6 seems to slow down the boot process.

If you do not need Bluetooth, you could try temporarily disabling the Bluetooth device(s) in the computer's BIOS to check whether this speeds up the boot process.
If you do not need iv6, you could also try disabling all ipv6 functionality in the network settings to check whether this helps reducing boot time.

Your boot log shows a total boot time of 34.4 seconds; this does not match the 1.5 minutes that you write in the question's title.
Do you have a long hidden timeout period in the grub settings?

Good idea. What is the output of:

grep -i time /etc/default/grub

Thanks

#GRUB_HIDDEN_TIMEOUT=0
GRUB_HIDDEN_TIMEOUT_QUIET=true
GRUB_TIMEOUT=10

this is the output of grep -i time/etc/default/grub

There is a ten seconds delay for showing the grub menu.
If you edit the grub settings and change
GRUB_TIMEOUT=10
into
GRUB_TIMEOUT=3
you will reduce the total time by seven seconds.

Commands to do that:
sudo gedit /etc/default/grub
sudo update-grub

well! decrement of grub time out helped me
what is ipv6? how to disable this?

..................thanks to all for helping me

see https://wiki.ubuntu.com/IPv6 especially first and last paragraphs

(I am not sure if that will make a reasonable difference in booting.)

Run:

sudo gedit /etc/default/grub; sudo update-grub

As one command, one gedit loads, change:
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"

To:
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash ipv6.disable=1"

Save the new file and close gedit. Once the configuration has applied, reboot the system.

If you want to reverse the setting, simply remove the added option and rerun:
sudo update-grub

Then reboot once more

what if i do sudo apt-get purge nvidia

is it so that this may increase boot speed as i don't have an nividia graphics card...... sorry for silly question as am new to ubuntu

Are you sure that you have NVidia drivers installed?

What is the output of
dpkg -l | grep -i nvidia
?

nothing is showing @ Manfred Hampl

In that case you do not have any NVidia driver installed, and there is no need to remove them.
How long does booting Ubuntu now take?

it is approximately 1 min now
@Manfred Hampl

Is that acceptable, or do you need to try reducing further?

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