Transcript Document

Improvement of bootup time
using Power Management
- Project Update Hiroki Kaminaga
Sony Corporation
[email protected]
2006/JAN/20
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Summary：
• Studied to make bootup time faster using
Suspend-to-disk technology
• Saving snapshot in each phase during
development (e.g. for verification)
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Stories so far：
• Ported swsusp function onto ARM
– Kernel: 2.6.11
• Ported suspend2 function onto ARM
(suspend2-2.2-rc9)
– Kernel: 2.6.14
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Status of Suspend2 ：
• 2.2-rc9: Already ported onto ARM
• 2.2-rc13: ARM support was incorporated in
suspend2
• 2.2-rc16: Now debugging ARM version（Now
very hot）
• Evaluated on 2.2-rc14 for today’s presentation
（The Latest version whose operation is
confirmed）
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Environment：
• Target Board
– OMAP Starter Kit
(OSK 5912)
• OS
– Linux 2.6
• Boot loader
– U-boot
• Image destination
– Flash ROM
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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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Measurement：
• Used printk times
$ make menuconfig
Kernel hacking --->
[*] Show timing information on printks
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Measurement Results：
ash
un-hibernate start [sec]
un-hibernate end [sec]
un-hibernate delta [sec]
read data delta [sec]
read cache delta [sec]
read total delta [sec]
other [sec]
image size [MB]
read speed [MB/sec]
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3.5919373
12.321754
8.729781
2.183252
2.562088
4.745340
3.984441
11.79687
2.4859
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3.591987
15.941194
12.349207
2.185462
5.995782
8.181244
4.167963
20.61718
2.5200
Log…
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Read Speed of NOR FLASH：
• MT28F128J3FS-12 ET
– 16 bit / 120ns Read Cycle
（From Datasheet） → 15.894 MB/s
– $ time dd if=/dev/mtdblock3 of=/dev/null \
bs=1024 count=10240
user 0.07 sys 2.25
→ 4.44 MB/s
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Issues：
• Bottleneck analysis using performance
analyzer etc.
→to reduce bootup time
• Debugging tool
→to analyze bug of rcXX
→LKST? LTT? SystemTap?
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Misc.：
• To speed up the image reading with DMA
transfer?
• To start Un-hibernate earlier?
• Collaboration with boot loader
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EOF
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