Module: xenomai-3
Branch: next
Commit: ccc6a6235ccf2c124adc273c20aaeca53ecff6b0
URL:
http://git.xenomai.org/?p=xenomai-3.git;a=commit;h=ccc6a6235ccf2c124adc273c20aaeca53ecff6b0
Author: Philippe Gerum <r...@xenomai.org>
Date: Sat Nov 14 16:41:13 2015 +0100
cobalt/powerpc: drop support for unlocked context switch
This feature never actually brought any measurable gain on powerpc
platforms, compared to the complexity of its implementation in the
pipeline. It was primarily aimed at reducing latency for interrupt
handlers when costly cache and TLB flushes are required to switch
context, at the expense of increasing the scheduling latency. It
turned out to be counter-productive on common powerpc platforms, with
efficient MMUs.
This feature has been default off for a while now, and 4.1+ pipelines
won't provide support for it anymore. Time to drop support from
Xenomai too.
---
kernel/cobalt/arch/powerpc/Kconfig | 20 +-------------------
1 file changed, 1 insertion(+), 19 deletions(-)
diff --git a/kernel/cobalt/arch/powerpc/Kconfig
b/kernel/cobalt/arch/powerpc/Kconfig
index 40eae0b..1cabef3 100644
--- a/kernel/cobalt/arch/powerpc/Kconfig
+++ b/kernel/cobalt/arch/powerpc/Kconfig
@@ -5,29 +5,11 @@ config XENO_ARCH_MATH_EMU
bool
default y if MATH_EMU || MATH_EMULATION
-config IPIPE_WANT_PREEMPTIBLE_SWITCH
- bool
- default y if XENO_ARCH_UNLOCKED_SWITCH
- default n if !XENO_ARCH_UNLOCKED_SWITCH
-
config XENO_ARCH_FPU
def_bool PPC_FPU
config XENO_ARCH_SYS3264
def_bool n
-menu "Machine/platform-specific options"
-
config XENO_ARCH_UNLOCKED_SWITCH
- bool "Unlocked context switch"
- depends on IPIPE_HAVE_PREEMPTIBLE_SWITCH
- default y
- help
-
- The Cobalt core may allow non-atomic execution of the
- machine-dependent context switching code, so that other CPUs
- and/or local interrupts may execute concurrently.
-
- This option reduces interrupt latency when costly cache and
- TLB flushes are required to switch context.
-endmenu
+ def_bool n
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