Commit-ID: 9a89b02918c03d91e685d06e49a652da5f35befc Gitweb: http://git.kernel.org/tip/9a89b02918c03d91e685d06e49a652da5f35befc Author: Ingo Molnar <mingo@xxxxxxxxxx> AuthorDate: Thu, 23 Apr 2015 11:26:08 +0200 Committer: Ingo Molnar <mingo@xxxxxxxxxx> CommitDate: Tue, 19 May 2015 15:47:22 +0200 x86/fpu: Print out whether we are doing lazy/eager FPU context switches Ever since the kernel started defaulting to eager FPU switches on modern Intel CPUs it's not been obvious whether a given system is using the lazy or the eager FPU context switching logic. So generate a boot message about which mode the FPU code is in: x86/fpu: Using 'lazy' FPU context switches. or: x86/fpu: Using 'eager' FPU context switches. Reviewed-by: Borislav Petkov <bp@xxxxxxxxx> Cc: Andy Lutomirski <luto@xxxxxxxxxxxxxx> Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx> Cc: Fenghua Yu <fenghua.yu@xxxxxxxxx> Cc: H. Peter Anvin <hpa@xxxxxxxxx> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Cc: Oleg Nesterov <oleg@xxxxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> --- arch/x86/kernel/fpu/xsave.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/x86/kernel/fpu/xsave.c b/arch/x86/kernel/fpu/xsave.c index a52205b..61696c5 100644 --- a/arch/x86/kernel/fpu/xsave.c +++ b/arch/x86/kernel/fpu/xsave.c @@ -691,6 +691,8 @@ void __init_refok eager_fpu_init(void) if (eagerfpu == ENABLE) setup_force_cpu_cap(X86_FEATURE_EAGER_FPU); + printk_once(KERN_INFO "x86/fpu: Using '%s' FPU context switches.\n", eagerfpu == ENABLE ? "eager" : "lazy"); + if (!cpu_has_eager_fpu) { stts(); return; -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
![]() |