From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoffer Dall Subject: Re: [PATCH v3 0/2] arm/arm64: KVM: Optimize arm64 fp/simd, saves 30-50% on exits Date: Wed, 1 Jul 2015 11:49:10 +0200 Message-ID: <20150701094910.GF11332@cbox> References: <1435190652-5831-1-git-send-email-m.smarduch@samsung.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <1435190652-5831-1-git-send-email-m.smarduch@samsung.com> Sender: kvm-owner@vger.kernel.org To: Mario Smarduch Cc: kvmarm@lists.cs.columbia.edu, marc.zyngier@arm.com, linux-arm-kernel@lists.infradead.org, kvm@vger.kernel.org, catalin.marinas@arm.com, will.deacon@arm.com List-Id: kvmarm@lists.cs.columbia.edu On Wed, Jun 24, 2015 at 05:04:10PM -0700, Mario Smarduch wrote: > Currently we save/restore fp/simd on each exit. Fist patch optimizes arm64 > save/restore, we only do so on Guest access. hackbench and > several lmbench tests show anywhere from 30% to above 50% optimzation > achieved. > > In second patch 32-bit handler is updated to keep exit handling consistent > with 64-bit code. 30-50% of what? The overhead or overall performance? > > Changes since v1: > - Addressed Marcs comments > - Verified optimization improvements with lmbench and hackbench, updated > commit message > > Changes since v2: > - only for patch 2/2 > - Reworked trapping to vfp access handler > > Changes since v3: > - Only for patch 2/2 > - Removed load_vcpu in switch_to_guest_vfp per Marcs comment > - Got another chance to replace an unreferenced label with a comment > > > Mario Smarduch (2): > Optimize arm64 skip 30-50% vfp/simd save/restore on exits > keep arm vfp/simd exit handling consistent with arm64 > > arch/arm/kvm/interrupts.S | 14 +++++++----- > arch/arm64/include/asm/kvm_arm.h | 5 ++++- > arch/arm64/kvm/hyp.S | 46 +++++++++++++++++++++++++++++++++++--- > 3 files changed, 55 insertions(+), 10 deletions(-) > > -- > 1.7.9.5 >