Self/Fast Boot use on SKY Boards
In many mission critical systems,
it is important to get an application up and running as fast as
possible.
The
SKY Self/Fast
Boot capability
provides the fastest application start time in the industry.
Note that
although the following example was done on the Enhanced 9U SKYbolt, the
same general information also applies to the Thunderbolt and
LightningBolt 6U products with the 6U products starting somewhat
faster.
Example:
A
Synthetic-Aperture
Radar (SAR) system
configured with 16 Enhanced SKYbolt 9U boards for a total of
256 processors. In Fast boot mode this application took approximately
12 seconds to boot from a cold start (or from a VME reset). This is in
contrast with the 10-15 minutes or more, that a typical
application restart or startup might take on a system this size running
in standard mode.
What Really Happens During Fast
Boot?
For the
SKYbolts to run a user application, we need to do the following:
- Load the monitor onto
each of the Support Processors on each board.
- Load the kernel onto
each of the application processors (16) on each board.
- Load the application
onto each of the
application processors (16) on each board.
Each of these
loads occur internally to each SKYbolt board at the speed of the
internal SKYbolt busses; we are not limited to the speed of the VME
bus, the host VME interface or the disk. These program loads also occur
in parallel so the startup time is independent of the number of SKY
boards in the system.
What Happens Without Fast Boot?
Without fast
boot (for example during code development), we need to do the
following:
- Load the monitor onto
each of the Support Processor and the kernel onto
each of application processors (16 processors) on each board. This is
done by the BOLT2admin utility and typically requires approximately 4
minutes for 16 boards.
- Load the application
onto each of the
application processors (up to 16) on each board. This requires 10
seconds per board or 2 1/2 minutes for the 16 boards.
Thus from power
on to a running application takes 6-7 minutes to load and start this
application. Bigger applications would take longer to start, smaller
applications take less time.
Sample Times With and Without
Fast Boot
The following table shows program
sizes and fastboot times (times in seconds) for 2 test cases. Times do
not include resetting the host card.
| Program
Size |
| Sample
applications |
2DFFT
|
SAR
|
| Lines of
C Code (Application) |
1,600 |
31,000 |
| Binary
Size (Bytes) |
172 K |
1,500 K |
| Normal Startup
(seconds) |
| 16
Processors |
26 |
30 |
| 256
Processors |
416 |
550 |
| Fast Boot
(seconds) |
| 16
Processors |
10 |
12 |
| 256
Processors |
10 |
12 |
For more information, contact SKY at:
