From 278d91c4609d55202c1e63d5fc5f01466cc7bbab Mon Sep 17 00:00:00 2001 From: Akira Takeuchi Date: Wed, 27 Oct 2010 17:28:52 +0100 Subject: MN10300: Make the FPU operate in non-lazy mode under SMP Make the FPU operate in non-lazy mode under SMP so that when the process that is currently using the FPU migrates to a different CPU, we don't have to ping its previous CPU to flush the FPU context. Signed-off-by: Akira Takeuchi Signed-off-by: Kiyoshi Owada Signed-off-by: David Howells --- arch/mn10300/Kconfig | 15 +++++++++++++++ 1 file changed, 15 insertions(+) (limited to 'arch/mn10300/Kconfig') diff --git a/arch/mn10300/Kconfig b/arch/mn10300/Kconfig index 7bd920b1c06f..a1f334ce0a36 100644 --- a/arch/mn10300/Kconfig +++ b/arch/mn10300/Kconfig @@ -140,6 +140,21 @@ config FPU default y depends on MN10300_PROC_MN103E010 +config LAZY_SAVE_FPU + bool "Save FPU state lazily" + default y + depends on FPU && !SMP + help + Enable this to be lazy in the saving of the FPU state to the owning + task's thread struct. This is useful if most tasks on the system + don't use the FPU as only those tasks that use it will pass it + between them, and the state needn't be saved for a task that isn't + using it. + + This can't be so easily used on SMP as the process that owns the FPU + state on a CPU may be currently running on another CPU, so for the + moment, it is disabled. + source "arch/mn10300/mm/Kconfig.cache" config MN10300_TLB_USE_PIDR -- cgit v1.2.2