> On 27/01/2016 08:33, Liang Li wrote: > > buffer_find_nonzero_offset() is a hot function during live migration. > > Now it use SSE2 instructions for optimization. For platform supports > > AVX2 instructions, use the AVX2 instructions for optimization can help > > to improve the performance of zero page checking about 30% comparing > > to SSE2. > > Live migration 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, execute the AVX2 instructions, > > else, execute the original instructions. > > > > With this patch, the QEMU binary can run on both platforms support > > AVX2 or not. > > > > Compiler which doesn't support the AVX2 and ifunc attribute can also > > build the source code successfully. > > > > v5 -> v4 changes: > > * Enhance the ifunc attribute detection (Paolo's suggestion) > > > > v3 -> v4 changes: > > * Use the GCC #pragma to make things simple (Paolo's suggestion) > > * Put avx2 related code in cutils.c (Richard's suggestion) > > * Change the configure, detect ifunc and avx2 attributes together > > > > 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 (2): > > configure: detect ifunc and avx2 attribute > > cutils: add avx2 instruction optimization > > > > configure | 21 +++++++++ > > include/qemu-common.h | 8 +--- > > util/cutils.c | 118 > ++++++++++++++++++++++++++++++++++++++++++++++++-- > > 3 files changed, 136 insertions(+), 11 deletions(-) > > Reviewed-by: Paolo Bonzini <pbonz...@redhat.com>
This patch set is pending here for a long time, who can help to make it merged? Liang
