I have been having rather slow boot on Ubuntu 12.04. Lately, I tried to figure out the reason and it seems to be the network connection which does not get connected and requires multiple attempts. Here is part of dmesg

[    2.174349] EXT4-fs (sda2): INFO: recovery required on readonly filesystem
[    2.174352] EXT4-fs (sda2): write access will be enabled during recovery
[    2.308172] firewire_core: created device fw0: GUID 384fc00005198d58, S400
[    2.333457] usb 7-1.2: new low-speed USB device number 3 using uhci_hcd
[    2.465896] EXT4-fs (sda2): recovery complete
[    2.466406] EXT4-fs (sda2): mounted filesystem with ordered data mode. Opts: (null)
[    2.589440] usb 7-1.3: new low-speed USB device number 4 using uhci_hcd
**[   18.292029] ADDRCONF(NETDEV_UP): eth0: link is not ready**
[   18.458958] udevd[377]: starting version 175
[   18.639482] Adding 4200960k swap on /dev/sda5.  Priority:-1 extents:1 across:4200960k 
[   19.314127] wmi: Mapper loaded
[   19.426602] r592 0000:09:01.2: PCI INT B -> GSI 18 (level, low) -> IRQ 18
[   19.426739] r592: driver successfully loaded
[   19.460105] input: Dell WMI hotkeys as /devices/virtual/input/input5
[   19.493629] lp: driver loaded but no devices found
[   19.497012] cfg80211: Calling CRDA to update world regulatory domain
[   19.535523] ACPI Warning: _BQC returned an invalid level (20110623/video-480)
[   19.539457] acpi device:03: registered as cooling_device2
[   19.539520] input: Video Bus as /devices/LNXSYSTM:00/device:00/PNP0A08:00/device:01/LNXVIDEO:00/input/input6
[   19.539568] ACPI: Video Device [M86] (multi-head: yes  rom: no  post: no)
[   19.578060] Linux video capture interface: v2.00
[   19.667708] dcdbas dcdbas: Dell Systems Management Base Driver (version 5.6.0-3.2)
[   19.763171] r852 0000:09:01.3: PCI INT B -> GSI 18 (level, low) -> IRQ 18
[   19.763258] r852: driver loaded successfully
[   19.854769] input: Microsoft Comfort Curve Keyboard 2000 as /devices/pci0000:00/0000:00:1d.1/usb7/7-1/7-1.2/7-1.2:1.0/input/input7
[   19.854864] generic-usb 0003:045E:00DD.0001: input,hidraw0: USB HID v1.11 Keyboard [Microsoft Comfort Curve Keyboard 2000] on usb-0000:00:1d.1-1.2/input0
[   19.878605] input: Microsoft Comfort Curve Keyboard 2000 as /devices/pci0000:00/0000:00:1d.1/usb7/7-1/7-1.2/7-1.2:1.1/input/input8
[   19.878698] generic-usb 0003:045E:00DD.0002: input,hidraw1: USB HID v1.11 Device [Microsoft Comfort Curve Keyboard 2000] on usb-0000:00:1d.1-1.2/input1
[   19.902779] input: DELL DELL USB Laser Mouse as /devices/pci0000:00/0000:00:1d.1/usb7/7-1/7-1.3/7-1.3:1.0/input/input9
[   19.925034] generic-usb 0003:046D:C063.0003: input,hidraw2: USB HID v1.10 Mouse [DELL DELL USB Laser Mouse] on usb-0000:00:1d.1-1.3/input0
[   19.925057] usbcore: registered new interface driver usbhid
[   19.925059] usbhid: USB HID core driver
[   19.942362] uvcvideo: Found UVC 1.00 device Laptop_Integrated_Webcam_2M (0c45:63ea)
[   19.947004] input: Laptop_Integrated_Webcam_2M as /devices/pci0000:00/0000:00:1a.7/usb1/1-6/1-6:1.0/input/input10
[   19.947075] usbcore: registered new interface driver uvcvideo
[   19.947077] USB Video Class driver (1.1.1)
[   20.145232] Intel(R) Wireless WiFi Link AGN driver for Linux, in-tree:
[   20.145235] Copyright(c) 2003-2011 Intel Corporation
[   20.145327] iwlwifi 0000:04:00.0: PCI INT A -> GSI 17 (level, low) -> IRQ 17
[   20.145357] iwlwifi 0000:04:00.0: setting latency timer to 64
[   20.145402] iwlwifi 0000:04:00.0: pci_resource_len = 0x00002000
[   20.145404] iwlwifi 0000:04:00.0: pci_resource_base = ffffc90000674000
[   20.145407] iwlwifi 0000:04:00.0: HW Revision ID = 0x0
[   20.145531] iwlwifi 0000:04:00.0: irq 46 for MSI/MSI-X
[   20.145613] iwlwifi 0000:04:00.0: Detected Intel(R) WiFi Link 5100 AGN, REV=0x54
[   20.145720] iwlwifi 0000:04:00.0: L1 Enabled; Disabling L0S
[   20.167535] iwlwifi 0000:04:00.0: device EEPROM VER=0x11f, CALIB=0x4
[   20.167538] iwlwifi 0000:04:00.0: Device SKU: 0Xf0
[   20.167567] iwlwifi 0000:04:00.0: Tunable channels: 13 802.11bg, 24 802.11a channels
[   20.172779] fglrx: module license 'Proprietary. (C) 2002 - ATI Technologies, Starnberg, GERMANY' taints kernel.
[   20.172783] Disabling lock debugging due to kernel taint
[   20.250115] [fglrx] Maximum main memory to use for locked dma buffers: 3759 MBytes.
[   20.250567] [fglrx]   vendor: 1002 device: 9553 count: 1
[   20.251256] [fglrx] ioport: bar 1, base 0x2000, size: 0x100
[   20.251271] pci 0000:01:00.0: PCI INT A -> GSI 16 (level, low) -> IRQ 16
[   20.251277] pci 0000:01:00.0: setting latency timer to 64
[   20.251559] [fglrx] Kernel PAT support is enabled
[   20.251578] [fglrx] module loaded - fglrx 8.96.4 [Mar 12 2012] with 1 minors
[   20.310385] iwlwifi 0000:04:00.0: loaded firmware version 8.83.5.1 build 33692
[   20.310598] Registered led device: phy0-led
[   20.310628] cfg80211: Ignoring regulatory request Set by core since the driver uses its own custom regulatory domain
[   20.372306] ieee80211 phy0: Selected rate control algorithm 'iwl-agn-rs'
[   20.411015] psmouse serio1: synaptics: Touchpad model: 1, fw: 7.2, id: 0x1c0b1, caps: 0xd04733/0xa40000/0xa0000
[   20.454232] input: SynPS/2 Synaptics TouchPad as /devices/platform/i8042/serio1/input/input11
[   20.545636] cfg80211: Ignoring regulatory request Set by core since the driver uses its own custom regulatory domain
[   20.545640] cfg80211: World regulatory domain updated:
[   20.545642] cfg80211:     (start_freq - end_freq @ bandwidth), (max_antenna_gain, max_eirp)
[   20.545644] cfg80211:     (2402000 KHz - 2472000 KHz @ 40000 KHz), (300 mBi, 2000 mBm)
[   20.545647] cfg80211:     (2457000 KHz - 2482000 KHz @ 20000 KHz), (300 mBi, 2000 mBm)
[   20.545649] cfg80211:     (2474000 KHz - 2494000 KHz @ 20000 KHz), (300 mBi, 2000 mBm)
[   20.545652] cfg80211:     (5170000 KHz - 5250000 KHz @ 40000 KHz), (300 mBi, 2000 mBm)
[   20.545654] cfg80211:     (5735000 KHz - 5835000 KHz @ 40000 KHz), (300 mBi, 2000 mBm)
[   20.609484] type=1400 audit(1340502633.160:2): apparmor="STATUS" operation="profile_load" name="/sbin/dhclient" pid=693 comm="apparmor_parser"
[   20.609494] type=1400 audit(1340502633.160:3): apparmor="STATUS" operation="profile_replace" name="/sbin/dhclient" pid=642 comm="apparmor_parser"
[   20.609843] type=1400 audit(1340502633.160:4): apparmor="STATUS" operation="profile_load" name="/usr/lib/NetworkManager/nm-dhcp-client.action" pid=693 comm="apparmor_parser"
[   20.609852] type=1400 audit(1340502633.160:5): apparmor="STATUS" operation="profile_replace" name="/usr/lib/NetworkManager/nm-dhcp-client.action" pid=642 comm="apparmor_parser"
[   20.610047] type=1400 audit(1340502633.160:6): apparmor="STATUS" operation="profile_load" name="/usr/lib/connman/scripts/dhclient-script" pid=693 comm="apparmor_parser"
[   20.610060] type=1400 audit(1340502633.160:7): apparmor="STATUS" operation="profile_replace" name="/usr/lib/connman/scripts/dhclient-script" pid=642 comm="apparmor_parser"
[   20.610476] type=1400 audit(1340502633.160:8): apparmor="STATUS" operation="profile_replace" name="/sbin/dhclient" pid=814 comm="apparmor_parser"
[   20.610829] type=1400 audit(1340502633.160:9): apparmor="STATUS" operation="profile_replace" name="/usr/lib/NetworkManager/nm-dhcp-client.action" pid=814 comm="apparmor_parser"
[   20.611035] type=1400 audit(1340502633.160:10): apparmor="STATUS" operation="profile_replace" name="/usr/lib/connman/scripts/dhclient-script" pid=814 comm="apparmor_parser"
[   20.661912] snd_hda_intel 0000:00:1b.0: PCI INT A -> GSI 22 (level, low) -> IRQ 22
[   20.661982] snd_hda_intel 0000:00:1b.0: irq 47 for MSI/MSI-X
[   20.662013] snd_hda_intel 0000:00:1b.0: setting latency timer to 64
[   20.770289] input: HDA Intel Mic as /devices/pci0000:00/0000:00:1b.0/sound/card0/input12
[   20.770689] snd_hda_intel 0000:01:00.1: PCI INT B -> GSI 17 (level, low) -> IRQ 17
[   20.770786] snd_hda_intel 0000:01:00.1: irq 48 for MSI/MSI-X
[   20.770815] snd_hda_intel 0000:01:00.1: setting latency timer to 64
[   20.994040] HDMI status: Codec=0 Pin=3 Presence_Detect=0 ELD_Valid=0
[   20.994189] input: HDA ATI HDMI HDMI/DP,pcm=3 as /devices/pci0000:00/0000:00:01.0/0000:01:00.1/sound/card1/input13
[   21.554799] vesafb: mode is 1024x768x32, linelength=4096, pages=0
[   21.554802] vesafb: scrolling: redraw
[   21.554804] vesafb: Truecolor: size=0:8:8:8, shift=0:16:8:0
[   21.557342] vesafb: framebuffer at 0xd0000000, mapped to 0xffffc90011800000, using 3072k, total 3072k
[   21.557498] Console: switching to colour frame buffer device 128x48
[   21.557516] fb0: VESA VGA frame buffer device
[   21.987338] EXT4-fs (sda2): re-mounted. Opts: errors=remount-ro
[   22.184693] EXT4-fs (sda6): mounted filesystem with ordered data mode. Opts: (null)
[   27.362440] iwlwifi 0000:04:00.0: RF_KILL bit toggled to disable radio.
[   27.436988] init: failsafe main process (986) killed by TERM signal
[   27.970112] ppdev: user-space parallel port driver
[   28.198917] Bluetooth: Core ver 2.16
[   28.198935] NET: Registered protocol family 31
[   28.198937] Bluetooth: HCI device and connection manager initialized
[   28.198940] Bluetooth: HCI socket layer initialized
[   28.198941] Bluetooth: L2CAP socket layer initialized
[   28.198947] Bluetooth: SCO socket layer initialized
[   28.226135] Bluetooth: RFCOMM TTY layer initialized
[   28.226141] Bluetooth: RFCOMM socket layer initialized
[   28.226143] Bluetooth: RFCOMM ver 1.11
[   28.445620] Bluetooth: BNEP (Ethernet Emulation) ver 1.3
[   28.445623] Bluetooth: BNEP filters: protocol multicast
[   28.524578] type=1400 audit(1340502641.076:11): apparmor="STATUS" operation="profile_load" name="/usr/lib/cups/backend/cups-pdf" pid=1052 comm="apparmor_parser"
[   28.525018] type=1400 audit(1340502641.076:12): apparmor="STATUS" operation="profile_load" name="/usr/sbin/cupsd" pid=1052 comm="apparmor_parser"
[   28.629957] type=1400 audit(1340502641.180:13): apparmor="STATUS" operation="profile_replace" name="/sbin/dhclient" pid=1105 comm="apparmor_parser"
[   28.630325] type=1400 audit(1340502641.180:14): apparmor="STATUS" operation="profile_replace" name="/usr/lib/NetworkManager/nm-dhcp-client.action" pid=1105 comm="apparmor_parser"
[   28.630535] type=1400 audit(1340502641.180:15): apparmor="STATUS" operation="profile_replace" name="/usr/lib/connman/scripts/dhclient-script" pid=1105 comm="apparmor_parser"
[   28.645266] type=1400 audit(1340502641.196:16): apparmor="STATUS" operation="profile_load" name="/usr/lib/lightdm/lightdm/lightdm-guest-session-wrapper" pid=1104 comm="apparmor_parser"
**[   28.751922] ADDRCONF(NETDEV_UP): wlan0: link is not ready**
[   28.753653] tg3 0000:08:00.0: irq 49 for MSI/MSI-X
**[   28.856127] ADDRCONF(NETDEV_UP): eth0: link is not ready
[   28.857034] ADDRCONF(NETDEV_UP): eth0: link is not ready**
[   28.871080] type=1400 audit(1340502641.420:17): apparmor="STATUS" operation="profile_load" name="/usr/lib/telepathy/mission-control-5" pid=1108 comm="apparmor_parser"
[   28.871519] type=1400 audit(1340502641.420:18): apparmor="STATUS" operation="profile_load" name="/usr/lib/telepathy/telepathy-*" pid=1108 comm="apparmor_parser"
[   28.874905] type=1400 audit(1340502641.424:19): apparmor="STATUS" operation="profile_replace" name="/usr/lib/cups/backend/cups-pdf" pid=1113 comm="apparmor_parser"
[   28.875354] type=1400 audit(1340502641.424:20): apparmor="STATUS" operation="profile_replace" name="/usr/sbin/cupsd" pid=1113 comm="apparmor_parser"
[   30.477976] tg3 0000:08:00.0: eth0: Link is up at 100 Mbps, full duplex
[   30.477979] tg3 0000:08:00.0: eth0: Flow control is on for TX and on for RX
**[   30.478390] ADDRCONF(NETDEV_CHANGE): eth0: link becomes ready**
[   31.110269] fglrx_pci 0000:01:00.0: irq 50 for MSI/MSI-X
[   31.110859] [fglrx] Firegl kernel thread PID: 1327
[   31.111021] [fglrx] Firegl kernel thread PID: 1329
[   31.111408] [fglrx] Firegl kernel thread PID: 1330
[   31.111543] [fglrx] IRQ 50 Enabled
[   31.712938] [fglrx] Gart USWC size:1224 M.
[   31.712941] [fglrx] Gart cacheable size:486 M.
[   31.712945] [fglrx] Reserved FB block: Shared offset:0, size:1000000 
[   31.712948] [fglrx] Reserved FB block: Unshared offset:fc2b000, size:3d5000 
[   31.712950] [fglrx] Reserved FB block: Unshared offset:1fffb000, size:5000 
[   41.312020] eth0: no IPv6 routers present

As you can see I get multiple instances of [ 28.856127] ADDRCONF(NETDEV_UP): eth0: link is not ready and then finally it becomes read and I get the message [ 30.478390] ADDRCONF(NETDEV_CHANGE): eth0: link becomes ready.

I searched askubuntun, ubuntuforum, and the web but couldn't find a solution. Any help would be very much appreciated.

Here is the bootchart