Transcript Power Management Discussion Hiroki Kaminaga Sony Corporation [email protected] [translated by [email protected]] 2005/Sept/30 JapanTechnicalJamboree4 Goal : • Want to shorten start up time of application HW Mounting Initialization drivers (Boot loader init / kernel) 1 [s]

Power Management
Discussion
Hiroki Kaminaga
Sony Corporation
[email protected]
[translated by [email protected]]
2005/Sept/30
JapanTechnicalJamboree4
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Goal :
• Want to shorten start up time of application
HW
Mounting
Initialization drivers
(Boot loader
init
/ kernel)
1 [s] 1 [s]
2 [s]
Startup time of application
5 [s]
• Processing until the application reaches to main()
– Transfer of image
– Dynamic linking
– Global constructors
• IPC Processing among applications for the whole system running
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Conventional Approaches:
• Reduce dynamic linking time
– prelink
• Reduce time for global constructors
– Put constructors in the same place(Localization effect)
• Execute in place (XIP)
• Demand Paging of Data Section(From
Mizuyama’s presentation in the previous
Jamboree)
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Our Approaches:
• Use return from hibernation
– (1) BIOS (Boot loader) level
– (2) Kernel level
– (3) BIOS + kernel
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Suspend/Resume Sequence(1):
KERNEL
BOOT
LOADER
I/O Image
save save
I/O
init
OFF
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Image I/O
restore rest.
ON
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Suspend/Resume Sequence (2):
KERNEL
I/O
save
Image
save
I/O
I/O Image I/O
boot
init
s.d. restore rest.
BOOT
LOADER
OFF
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ON
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Suspend/Resume Sequence (3):
I/O img
KERNEL
save save
BOOT
LOADER
I/O img I/O
init rest rest.
I/O img
save save
I/O img I/O
init rest rest.
OFF
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ON
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Comparison of Three Approaches:
• (1) BIOS (Boot loader) level
– Relatively faster resume from hibernation
– Complicated processing required when data integrity lost
• (2) Kernel level
– Can process to ensure the data integrity after resume from
hibernation
– Slower resume from hibernation
• (3) BIOS + kernel
– Fast resume from hibernation
– Can process to ensure the data integrity
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Basic ideas:
• Startup
– Reduce processing until the un-hibernate on kernel side,
using helper function of Boot loader
• DEFERRED_RESUME
– Start up the specified application with high priority
• Saving system image
– To start always with the same state
• Others
– Mount
– Splash window
– High speed shutdown
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Hibernation on Linux:
• Swsusp
– Included in 2.6 vanilla kernel
(Documentation/power/swsusp.txt)
– Author: Pavel Machek
• Software suspend 2
– http://www.suspend2.net/
– Author: Nigel Cunningham
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Hibernate on Linux(comparison):
swsusp
suspend2
architecture
i386, ppc, x86_64, ia64
i386, ppc, x86_64
Discontiguous memory
○
×
Compression
Encryption
×
×
×
○
○
○
×
×
○
○
Suspend-to-swapfile
Suspend-to-file
Userland サポート
Source： http://www.suspend2.net/features
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Environment:
• Target board
– OMAP Starter Kit
(OSK 5912)
• OS
– Linux 2.6
• Boot loader
– U-boot
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Hardware Features:
ARM9 core operating at 192 Mhz.
DSP core operating at 192 Mhz.
TLV320AIC23 Stereo Codec
32 Mbyte DDR SDRAM
32 Mbyte Flash ROM
RS-232 Serial Port
10 MBPS Ethernet port
USB Host Port
Compact flash connector
On board IEEE 1149.1 JTAG
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Work Items:
• Choosing hibernation on Linux
– Trying with swsusp first
•
•
•
•
•
•
Porting to ARM
Hibernation onto FLASH
Saving system image
High speed shutdown
Hibernation on Boot loader
DEFERED_RESUME
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Current status:
• Investigating Suspend2
– Compression of system image
– Encryption of system image
• Porting Suspend2 onto ARM
• Investigating U-boot
– Hibernation on Boot loader side
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Demo:
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Community:
• Sent ARM port patch to Suspend2 ML;
Accepted favarably.
• ARM ML adviced me on questions/issues
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EOF
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Congraturation!
HanshinTigers
won the league championship
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