Path: csiph.com!news.freedyn.net!aioe.org!bofh.it!news.nic.it!robomod From: Andy Lutomirski Newsgroups: linux.kernel Subject: [PATCH 0/5] x86/fpu: eagerfpu fixes, speedups, and default enablement Date: Sat, 23 Jan 2016 02:00:02 +0100 Message-ID: X-Mailer: git-send-email 2.5.0 Sender: robomod@news.nic.it List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Approved: robomod@news.nic.it Lines: 39 Organization: linux.* mail to news gateway X-Original-Cc: Borislav Petkov , Fenghua Yu , Oleg Nesterov , Peter Zijlstra , Sai Praneeth Prakhya , yu-cheng yu , Dave Hansen , Rik van Riel , Linus Torvalds , Andy Lutomirski X-Original-Date: Fri, 22 Jan 2016 16:56:01 -0800 X-Original-Message-ID: X-Original-Sender: linux-kernel-owner@vger.kernel.org Xref: csiph.com linux.kernel:1315475 Hi all- Patches 1, 2, and 3 are fixes. Patch 4 is probably a small speedup. It also only matters in lazy FPU mode, which means that, most likely, no one cares. Apply or don't -- I don't care much. Patch 5 is, in some sense, a radical change. Currently we select eager or lazy mode depending on CPU type. I think that lazy mode sucks and that we should deprecate and remove it. With patches 1-3 applied, I think that eagerfpu works on all systems. Patch 5 will use it on all systems subject to a chicken flag -- eagerfpu=off will still disable it. I propose that we apply patch 5, let it soak in -next until the 4.6 merge window opens, possibly let it actually land in 4.6, and then remove lazy mode entirely for 4.7. This will open up enormous cleanup possibilities, and it will make the fpu code vastly more comprehensible. Thoughts? Andy Lutomirski (5): x86/fpu: Fix math emulation in eager fpu mode x86/fpu: Fix FNSAVE usage in eagerfpu mode x86/fpu: Fold fpu_copy into fpu__copy x86/fpu: Speed up lazy FPU restores slightly x86/fpu: Default eagerfpu=on on all CPUs arch/x86/include/asm/fpu/internal.h | 3 ++- arch/x86/kernel/fpu/core.c | 52 +++++++++++++++++++------------------ arch/x86/kernel/fpu/init.c | 13 ++++------ arch/x86/kernel/traps.c | 3 +-- 4 files changed, 35 insertions(+), 36 deletions(-) -- 2.5.0