From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030862AbbEEQ43 (ORCPT ); Tue, 5 May 2015 12:56:29 -0400 Received: from mail-wi0-f172.google.com ([209.85.212.172]:37558 "EHLO mail-wi0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760959AbbEEQ2y (ORCPT ); Tue, 5 May 2015 12:28:54 -0400 From: Ingo Molnar To: linux-kernel@vger.kernel.org Cc: Andy Lutomirski , Borislav Petkov , Dave Hansen , Fenghua Yu , "H. Peter Anvin" , Linus Torvalds , Oleg Nesterov , Thomas Gleixner Subject: [PATCH 044/208] x86/fpu: Print out whether we are doing lazy/eager FPU context switches Date: Tue, 5 May 2015 18:24:24 +0200 Message-Id: <1430843228-13749-45-git-send-email-mingo@kernel.org> X-Mailer: git-send-email 2.1.0 In-Reply-To: <1430843228-13749-1-git-send-email-mingo@kernel.org> References: <1430843228-13749-1-git-send-email-mingo@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 Cc: Andy Lutomirski Cc: Dave Hansen Cc: Fenghua Yu Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Oleg Nesterov Cc: Thomas Gleixner Signed-off-by: Ingo Molnar --- 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 a52205b87acb..61696c5005eb 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; -- 2.1.0