From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:48490) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1a6H6c-0007m5-8j for qemu-devel@nongnu.org; Tue, 08 Dec 2015 07:10:55 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1a6H6X-00031A-0V for qemu-devel@nongnu.org; Tue, 08 Dec 2015 07:10:53 -0500 Received: from mga11.intel.com ([192.55.52.93]:29823) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1a6H6W-00030i-RF for qemu-devel@nongnu.org; Tue, 08 Dec 2015 07:10:48 -0500 From: Liang Li Date: Tue, 8 Dec 2015 20:08:52 +0800 Message-Id: <1449576535-3369-1-git-send-email-liang.z.li@intel.com> Subject: [Qemu-devel] [v3 0/3] add avx2 instruction optimization List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Liang Li , quintela@redhat.com, mst@redhat.com, dgilbert@redhat.com, stefanha@redhat.com, amit.shah@redhat.com, pbonzini@redhat.com, rth@twiddle.net buffer_find_nonzero_offset() is a hot function during live migration. Now it use SSE2 intructions for optimization. For platform supports AVX2 instructions, use the AVX2 instructions for optimization can help to improve the performance about 30% comparing to SSE2. Zero page check can be faster with this optimization, the test result shows that for an 8GB RAM idle guest, this patch can help to shorten the total live migration time about 6%. This patch use the ifunc mechanism to select the proper function when running, for platform supports AVX2, excute the AVX2 instructions, else, excute the original code. With this patch, the QEMU binary can run on both platforms support AVX2 or not. Compiler which desn't support the AVX2 or ifunc attribute can build the source code successfully. v2 -> v3 changes: * Detect the ifunc attribute support (Paolo's suggestion) * Use the ifunc attribute instead of the inline asm (Richard's suggestion) * Change the configure (Juan's suggestion) Liang Li (3): cutils: add avx2 instruction optimization configure: detect ifunc attribute configure: add options to config avx2 configure | 50 +++++++++++++++++++++++++++++++++++++ include/qemu-common.h | 13 +++++----- util/Makefile.objs | 2 ++ util/buffer-zero-avx2.c | 54 ++++++++++++++++++++++++++++++++++++++++ util/cutils.c | 65 +++++++++++++++++++++++++++++++++++++++++++++++-- 5 files changed, 175 insertions(+), 9 deletions(-) create mode 100644 util/buffer-zero-avx2.c -- 1.9.1