From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bruce Richardson Subject: Re: [PATCH 0/4] DPDK memcpy optimization Date: Tue, 20 Jan 2015 16:14:53 +0000 Message-ID: <20150120161453.GA5316@bricha3-MOBL3> References: <1421632414-10027-1-git-send-email-zhihong.wang@intel.com> <20150119130221.GB21790@hmsreliant.think-freely.org> <20150120151118.GD18449@hmsreliant.think-freely.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: "dev-VfR2kkLFssw@public.gmane.org" To: Neil Horman Return-path: Content-Disposition: inline In-Reply-To: <20150120151118.GD18449-B26myB8xz7F8NnZeBjwnZQMhkBWG/bsMQH7oEaQurus@public.gmane.org> List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces-VfR2kkLFssw@public.gmane.org Sender: "dev" On Tue, Jan 20, 2015 at 10:11:18AM -0500, Neil Horman wrote: > On Tue, Jan 20, 2015 at 03:01:44AM +0000, Wang, Zhihong wrote: > > > > > > > -----Original Message----- > > > From: Neil Horman [mailto:nhorman-2XuSBdqkA4R54TAoqtyWWQ@public.gmane.org] > > > Sent: Monday, January 19, 2015 9:02 PM > > > To: Wang, Zhihong > > > Cc: dev-VfR2kkLFssw@public.gmane.org > > > Subject: Re: [dpdk-dev] [PATCH 0/4] DPDK memcpy optimization > > > > > > On Mon, Jan 19, 2015 at 09:53:30AM +0800, zhihong.wang-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org wrote: > > > > This patch set optimizes memcpy for DPDK for both SSE and AVX platforms. > > > > It also extends memcpy test coverage with unaligned cases and more test > > > points. > > > > > > > > Optimization techniques are summarized below: > > > > > > > > 1. Utilize full cache bandwidth > > > > > > > > 2. Enforce aligned stores > > > > > > > > 3. Apply load address alignment based on architecture features > > > > > > > > 4. Make load/store address available as early as possible > > > > > > > > 5. General optimization techniques like inlining, branch reducing, > > > > prefetch pattern access > > > > > > > > Zhihong Wang (4): > > > > Disabled VTA for memcpy test in app/test/Makefile > > > > Removed unnecessary test cases in test_memcpy.c > > > > Extended test coverage in test_memcpy_perf.c > > > > Optimized memcpy in arch/x86/rte_memcpy.h for both SSE and AVX > > > > platforms > > > > > > > > app/test/Makefile | 6 + > > > > app/test/test_memcpy.c | 52 +- > > > > app/test/test_memcpy_perf.c | 238 +++++--- > > > > .../common/include/arch/x86/rte_memcpy.h | 664 > > > +++++++++++++++------ > > > > 4 files changed, 656 insertions(+), 304 deletions(-) > > > > > > > > -- > > > > 1.9.3 > > > > > > > > > > > Are you able to compile this with gcc 4.9.2? The compilation of > > > test_memcpy_perf is taking forever for me. It appears hung. > > > Neil > > > > > > Neil, > > > > Thanks for reporting this! > > It should compile but will take quite some time if the CPU doesn't support AVX2, the reason is that: > > 1. The SSE & AVX memcpy implementation is more complicated than AVX2 version thus the compiler takes more time to compile and optimize > > 2. The new test_memcpy_perf.c contains 126 constants memcpy calls for better test case coverage, that's quite a lot > > > > I've just tested this patch on an Ivy Bridge machine with GCC 4.9.2: > > 1. The whole compile process takes 9'41" with the original test_memcpy_perf.c (63 + 63 = 126 constant memcpy calls) > > 2. It takes only 2'41" after I reduce the constant memcpy call number to 12 + 12 = 24 > > > > I'll reduce memcpy call in the next version of patch. > > > ok, thank you. I'm all for optimzation, but I think a compile that takes almost > 10 minutes for a single file is going to generate some raised eyebrows when end > users start tinkering with it > > Neil > > > Zhihong (John) > > Even two minutes is a very long time to compile, IMHO. The whole of DPDK doesn't take that long to compile right now, and that's with a couple of huge header files with routing tables in it. Any chance you could cut compile time down to a few seconds while still having reasonable tests? Also, when there is AVX2 present on the system, what is the compile time like for that code? /Bruce