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author | wdenk <wdenk> | 2003-04-05 00:53:31 +0000 |
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committer | wdenk <wdenk> | 2003-04-05 00:53:31 +0000 |
commit | 3e38691e8f7aa0d9b498d76c7279ddec6e4946f3 (patch) | |
tree | bec2e661298847dc5bcf9335ef31259686e882e1 /doc/README.sched | |
parent | 36c05a80ecbe3997abd9aa628a68dd6c0bacf681 (diff) | |
download | u-boot-imx-3e38691e8f7aa0d9b498d76c7279ddec6e4946f3.zip u-boot-imx-3e38691e8f7aa0d9b498d76c7279ddec6e4946f3.tar.gz u-boot-imx-3e38691e8f7aa0d9b498d76c7279ddec6e4946f3.tar.bz2 |
* Patch by Arun Dharankar, 4 Apr 2003:
Add IDMA example code (tested on 8260 only)
* Add support for Purple Board (MIPS64 5Kc)
* Add support for MIPS64 5Kc CPUs
* Fix missing setting of "loadaddr" and "bootfile" on ARM and MIPS
* Patch by Denis Peter, 04 Apr 2003:
- update MIP405-4 board
* Patches by Denis Peter, 03 April 2003:
- fix PCI IRQs on MPL boards
- fix two more un-relocated pointer problems
* Fix behaviour of "run" command:
- print error message iv variable does not exist
- terminate processing of arguments in case of error
* Patches by Peter Figuli, 10 Mar 2003
- Add support for BTUART on PXA platform
- Add support for WEP EP250 (PXA) board
* Fix flash problems on INCA-IP; add tool to allow bruning images to
flash using a BDI2000
* Implement fix for I2C Edge Conditions problem for all boards that
use the bit-banging driver (common/soft_i2c.c)
* Add patches by Robert Schwebel, 31 Mar 2003:
- csb226 board: bring in sync with innokom/memsetup.S
- csb226 board: fix MDREFR handling
- misc doc fixes / extensions
- innokom board: cleanup, MDREFR fix in memsetup.S, config update
- add BOOT_PROGRESS to armlinux.c
Diffstat (limited to 'doc/README.sched')
-rw-r--r-- | doc/README.sched | 53 |
1 files changed, 53 insertions, 0 deletions
diff --git a/doc/README.sched b/doc/README.sched new file mode 100644 index 0000000..3aa89e6 --- /dev/null +++ b/doc/README.sched @@ -0,0 +1,53 @@ +Notes on the scheduler in sched.c: +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + + 'sched.c' provides an very simplistic multi-threading scheduler. + See the example, function 'sched(...)', in the same file for its + API usage. + + Until an exhaustive testing can be done, the implementation cannot + qualify as that of production quality. It works with the example + in 'sched.c', it may or may not work in other cases. + + +Limitations: +~~~~~~~~~~~~ + + - There are NO primitives for thread synchronization (locking, + notify etc). + + - Only the GPRs and FPRs context is saved during a thread context + switch. Other registers on the PowerPC processor (60x, 7xx, 7xxx + etc) are NOT saved. + + - The scheduler is NOT transparent to the user. The user + applications must invoke thread_yield() to allow other threads to + scheduler. + + - There are NO priorities, and the scheduling policy is round-robin + based. + + - There are NO capabilities to collect thread CPU usage, scheduler + stats, thread status etc. + + - The semantics are somewhat based on those of pthreads, but NOT + the same. + + - Only seven threads are allowed. These can be easily increased by + changing "#define MAX_THREADS" depending on the available memory. + + - The stack size of each thread is 8KBytes. This can be easily + increased depending on the requirement and the available memory, + by increasing "#define STK_SIZE". + + - Only one master/parent thread is allowed, and it cannot be + stopped or deleted. Any given thread is NOT allowed to stop or + delete itself. + + - There NOT enough safety checks as are probably in the other + threads implementations. + + - There is no parent-child relationship between threads. Only one + thread may thread_join, preferably the master/parent thread. + +(C) 2003 Arun Dharankar <ADharankar@ATTBI.Com> |