The following table shows the boot time savings using IFS Restoration,
as measured on an EDOSK7780 at 400 MHz.
Note that debug output is disabled.
| Restoration type
|
Image size
|
IFS compression
|
IFS checksum
|
Initial boot time
|
Subsequent boot time
|
Savings |
| Kernel
|
32.8 MB
|
UCL
|
No
|
8 s
|
< 0.5 s
|
7.5 s |
| Kernel
|
32.8 MB
|
UCL
|
Yes
|
8 s
|
< 1.0 s
|
7.0 s |
| Kernel
|
32.8 MB
|
None
|
No
|
7 s
|
< 0.5 s
|
6.5 s |
| Kernel
|
32.8 MB
|
None
|
Yes
|
7 s
|
< 1.0 s
|
6.0 s |
| Secondary IFS
|
32.0 MB (0.2 MB, 31.8 MB)
|
UCL (primary)
None (secondary)
|
No
|
7 s
|
< 0.5 s
|
6.5 s |
| Secondary IFS
|
32.0 MB (0.2 MB, 31.8 MB)
|
UCL (primary)
None (secondary)
|
Yes
|
7 s
|
< 1.0 s
|
6.0 s |
Note the following details regarding these performance numbers:
- Boot times don't include the time from power-on/reset vector but
from the point where the IPL scans and loads the image (add
10–50 ms to the times above).
- During initial boot, images are manually copied from flash to RAM
(i.e. no DMA).
- Boot times include the time to:
- copy the image from flash to RAM (on initial boot)
- run the startup and initialize the kernel
- start the serial driver and the shell
- Boot times don't include the time to start other drivers or user
applications.
- Time measurements are made to approximately 0.5 second granularity
(subsequent boot times are likely faster than reported).
- Boot time savings for uncompressed images are less because the
initial booting is faster than UCL compressed images (due to the time
it takes to uncompress the UCL image).