Boot-up Time Reduction Howto - Revision history

Wmat: Fixing broken links.

2010-01-28T01:45:35Z

Fixing broken links.

Wmat: Fixing broken links.

2010-01-28T01:42:19Z

Fixing broken links.

Wmat: Fixing broken links.

2010-01-28T01:41:25Z

Fixing broken links.

Wmat: Fixing broken links.

2010-01-28T01:37:27Z

Fixing broken links.

Wmat: Fixing broken links.

2010-01-28T01:35:35Z

Fixing broken links.

Wmat: Fixing broken links.

2010-01-28T01:34:33Z

Fixing broken links.

Wmat: Fixing broken links

2010-01-28T01:32:56Z

Fixing broken links

Wmat: Fixing broken links.

2010-01-28T01:29:49Z

Fixing broken links.

Berkus: /* User Space Phase */

2009-04-07T02:02:34Z

‎User Space Phase

Berkus: /* User Space Phase */

2009-04-07T02:01:47Z

‎User Space Phase

@@ Line 113: / Line 113: @@
 |[[IDE No Probe]]||Drivers||Use "noprobe" on kernel command line for IDE driver                          ||3 sec.||Depends on hardware present
 |-
-|[[Reduce Driver Busy Waits]]||Drivers||Reduce the length of driver busy waits                                       ||??||.
+|Reduce Driver Busy Waits||Drivers||Reduce the length of driver busy waits                                       ||??||.
 |-
 |[[Short IDE Delays]]||Drivers||Reduce length of IDE initialization delays                                   ||5 sec.||May be dangerous, depends on hardware
 |-
-|[[Threaded Init]]||Drivers||Replace busywaits in drivers with yields                                     ||??||Only adds value if driver can be parallelized with some other init activity.
+|Threaded Init||Drivers||Replace busywaits in drivers with yields                                     ||??||Only adds value if driver can be parallelized with some other init activity.
 |-
 |[[IDE Preempt]]||Drivers||Replace busywaits in IDE drivers with yields                                 ||250 ms (decreased non-preemptibility)||Already fixed in 2.6
 |-
-|[[Reduce RC Scripts]]||RC scripts||Eliminate unneeded init scripts                                              ||3 sec.||Depends on required scripts
+|Reduce RC Scripts||RC scripts||Eliminate unneeded init scripts                                              ||3 sec.||Depends on required scripts
 |-
 |[[Parallel RC Scripts]]||RC scripts||Start init scripts in parallel                                               ||??||.
 |-
-|[[Defer RC Scripts]]||RC scripts||Defer some init scripts to later in boot cycle                               ||??||.
+|Defer RC Scripts||RC scripts||Defer some init scripts to later in boot cycle                               ||??||.
 |-
 |[[Optimize RC Scripts]]||RC scripts||Use busybox, smaller shell, builtins, adjusted scripts                       ||3 sec.||Depends on required scripts
 |-
-|[[Custom Init Program]]||RC scripts|| Use custom initialization program (eliminating RC scripts altogether)       ||10 sec.||requires long-term maintenance of the program
+|Custom Init Program||RC scripts|| Use custom initialization program (eliminating RC scripts altogether)       ||10 sec.||requires long-term maintenance of the program
 |-
 |[[Application XIP]]||User Space||Use Execute-In-Place for applications and libraries.                         ||??||Requires uncompressed file system. Application performance may be reduced.
 |-
-|[[Segmented File System]]||User Space||Keep read-only data separate from writable data in flash storage             ||??||.
+|Segmented File System||User Space||Keep read-only data separate from writable data in flash storage             ||??||.
 |-
-|[[Reduce Flash Writes]]||User Space||Avoid writes to flash memory                                                 ||??||.
+|Reduce Flash Writes||User Space||Avoid writes to flash memory                                                 ||??||.
 |-
-|[[Ramdisk During Boot]]||User Space||Keep writable files in RAM, and write them to flash after boot               ||??||.
+|Ramdisk During Boot||User Space||Keep writable files in RAM, and write them to flash after boot               ||??||.
 |-
-|[[Smaller Programs]]||User Space||Use smallest programs and configurations possible                            ||??||Reduces program load time. It may increase cache hits.
+|Smaller Programs||User Space||Use smallest programs and configurations possible                            ||??||Reduces program load time. It may increase cache hits.
 |-
-|[[Faster Memory]]||General||Use faster memory                                                            ||??||.
+|Faster Memory||General||Use faster memory                                                            ||??||.
 |}

@@ Line 107: / Line 107: @@
 |[[Disable Console]]||Kernel||Turn off output to serial console during boot                                ||250 ms||.
 |-
-|[[Preconfigure PCI]]||Kernel||Preconfigure PCI bus slots on kernel command line                            ||??||Is this even possible?
+|Preconfigure PCI||Kernel||Preconfigure PCI bus slots on kernel command line                            ||??||Is this even possible?
 |-
-|[[Load Drivers Later]]||Drivers||Move drivers to modules and load them later in boot sequence.)               ||??||Only works for drivers that can be loaded as modules late in the boot cycle.
+|Load Drivers Later||Drivers||Move drivers to modules and load them later in boot sequence.)               ||??||Only works for drivers that can be loaded as modules late in the boot cycle.
 |-
 |[[IDE No Probe]]||Drivers||Use "noprobe" on kernel command line for IDE driver                          ||3 sec.||Depends on hardware present

@@ Line 103: / Line 103: @@
 |No Probe Missing Devices||Kernel||Avoid probing for non-existent keyboards and other devices                   ||??    ||.
 |-
-|[[Small Kernel Config]]||Kernel||Reduce kernel size and length of code paths, thereby reducing execution overhead||??||.
+|Small Kernel Config||Kernel||Reduce kernel size and length of code paths, thereby reducing execution overhead||??||.
 |-
 |[[Disable Console]]||Kernel||Turn off output to serial console during boot                                ||250 ms||.

@@ Line 95: / Line 95: @@
 |Skip Firmware||Firmware||Skip firmware probing features,  like memory check, bus probing, and device detection, etc.||??|| Linux re-probes busses and devices anyway, so this is usually waste of time
 |-
-|[[Parallel HD SpinUp]] ||Firwmare||Start hard drive spin up before loading kernel                               ||??    ||Not possible if the kernel is loaded from  hard drive.
+|[[Parallel HDSpin Up]] ||Firwmare||Start hard drive spin up before loading kernel                               ||??    ||Not possible if the kernel is loaded from  hard drive.
 |-
 |[[DMA Copy Of Kernel On Startup]]||Firmware||Use DMA to copy kernel from flash to RAM                                     ||180 ms||.
@@ Line 101: / Line 101: @@
 |[[Preset LPJ]]||Kernel||Use a hardcoded loops_per_jiffy value to avoid cost of calibration.          ||250 ms||.
 |-
-|[[No Probe Missing Devices]]||Kernel||Avoid probing for non-existent keyboards and other devices                   ||??    ||.
+|No Probe Missing Devices||Kernel||Avoid probing for non-existent keyboards and other devices                   ||??    ||.
 |-
 |[[Small Kernel Config]]||Kernel||Reduce kernel size and length of code paths, thereby reducing execution overhead||??||.

@@ Line 93: / Line 93: @@
 |[[Kernel XIP]]||Firmware||Kernel Execute-In-Place - avoids kernel copy and decompression time          ||250 ms||causes runtime performance loss
 |-
-|[[Skip Firmware]]||Firmware||Skip firmware probing features,  like memory check, bus probing, and device detection, etc.||??|| Linux re-probes busses and devices anyway, so this is usually waste of time
+|Skip Firmware||Firmware||Skip firmware probing features,  like memory check, bus probing, and device detection, etc.||??|| Linux re-probes busses and devices anyway, so this is usually waste of time
 |-
 |[[Parallel HD SpinUp]] ||Firwmare||Start hard drive spin up before loading kernel                               ||??    ||Not possible if the kernel is loaded from  hard drive.

@@ Line 62: / Line 62: @@
 *[[Application XIP]] - Execute-In-Place for applications and librarys
-*[[Reduce RC Scripts]] - Eliminate unneeded RC scripts
+*Reduce RC Scripts - Eliminate unneeded RC scripts
-*[[Custom Init Program]] - Use a custom initialization program
+*Custom Init Program - Use a custom initialization program
 **(This is a special case of eliminating unneeded RC scripts)
 *[[Optimize RC Scripts]] - Optimize RC script execution
 *[[Parallel RC Scripts]] - Execute RC scripts in parallel, instead of in sequence
 *[[Pre Linking]] - Avoid overhead of runtime link fixups during first program/library load
-*[[Reduce Flash Writes]] - Reduce writes to flash. (In particular, perhaps you want to "disable the date of last access" with noatime [http://forums.techarena.in/tips-tweaks/1053888.htm][http://stackoverflow.com/questions/81158/files-on-xp-is-turning-off-last-access-time-safe][http://beta.ivancover.com/wiki/index.php/Eee_PC_Linux#Less_Disk_Writes][http://home.x-pec.com/~ivc/sites/ivc/ibook/linux/][http://danweinreb.org/blog/using-solid-state-disks-on-linux][http://24.97.150.195/nstwiki/index.php/HowTo_Disable_The_%22relatime%22_Method_For_%22atime%22_Updates_For_A_File])
+*Reduce Flash Writes - Reduce writes to flash. (In particular, perhaps you want to "disable the date of last access" with noatime [http://forums.techarena.in/tips-tweaks/1053888.htm][http://stackoverflow.com/questions/81158/files-on-xp-is-turning-off-last-access-time-safe][http://beta.ivancover.com/wiki/index.php/Eee_PC_Linux#Less_Disk_Writes][http://home.x-pec.com/~ivc/sites/ivc/ibook/linux/][http://danweinreb.org/blog/using-solid-state-disks-on-linux][http://24.97.150.195/nstwiki/index.php/HowTo_Disable_The_%22relatime%22_Method_For_%22atime%22_Updates_For_A_File])
-*[[Disable Logging]] - Turn off logging to stable storage
+*Disable Logging - Turn off logging to stable storage
-*[[Faster File System]] - Use faster file system
+*Faster File System - Use faster file system
-*[[Ramdisk During Boot]] - Use RAMDISK during boot
+*Ramdisk During Boot - Use RAMDISK during boot
-*[[Segmented File System]] - Use a segmented file system to avoid interference between reads and writes
+*Segmented File System - Use a segmented file system to avoid interference between reads and writes
 == General Reduction Techniques ==

@@ Line 48: / Line 48: @@
 *DisableConsole - Turn off serial console output during boot
 *[[Preset LPJ]] - Use pre-set loops_per_jiffy (avoid calibrate_delay())
-*[[Preconfigure PCI]] -  Preconfigure some PCI bus slots
+*Preconfigure PCI -  Preconfigure some PCI bus slots
 *[[IDE No Probe]] - Don't probe some IDE devices -
-*[[No Probe Missing Devices]] - Disable probes for non-existent devices (including keyboards, etc.)
+*No Probe Missing Devices - Disable probes for non-existent devices (including keyboards, etc.)
-*[[Small Kernel Config]] - Use smallest kernel configuration possible
+*Small Kernel Config - Use smallest kernel configuration possible
-*[[Reduce Driver Busy Waits]] - Shorten device probes by reducing the amount of time the driver busywaits
+*Reduce Driver Busy Waits - Shorten device probes by reducing the amount of time the driver busywaits
 **A special case of this is [[Short IDE Delays]], with IDE driver delays
-*[[Threaded Init]] - Perform threaded initialization - replace driver busywaits with yields
+*Threaded Init - Perform threaded initialization - replace driver busywaits with yields
 **A special case of this is [[IDE Preempt]], with IDE driver busywaits
-*[[Load Drivers Later]] - Use modules where possible to move driver initialization later in the boot sequence
+*Load Drivers Later - Use modules where possible to move driver initialization later in the boot sequence
 == User Space Phase ==

@@ Line 40: / Line 40: @@
 *[[Kernel XIP]] - Kernel Execute-In-Place
 *SkipFirmware - Disable [[firmware]] features to eliminate diagnostics, memory counts, etc.
-*[[Parallel HD SpinUp]] - Parallelize Hard Disk spinup with Kernel load
+*[[Parallel HDSpin Up]] - Parallelize Hard Disk spinup with Kernel load
 *[[DMA Copy Of Kernel On Startup]] - Use DMA to copy kernel from flash to RAM