From: Marc Sune <marc.sune@bisdn.de>
To: dev@dpdk.org
Subject: Re: [dpdk-dev] [PATCH 0/4] DPDK memcpy optimization
Date: Wed, 21 Jan 2015 13:36:41 +0100 [thread overview]
Message-ID: <54BF9D59.7070104@bisdn.de> (raw)
In-Reply-To: <F60F360A2500CD45ACDB1D700268892D0E75F664@SHSMSX101.ccr.corp.intel.com>
On 21/01/15 04:44, Wang, Zhihong wrote:
>
>> -----Original Message-----
>> From: Richardson, Bruce
>> Sent: Wednesday, January 21, 2015 12:15 AM
>> To: Neil Horman
>> Cc: Wang, Zhihong; dev@dpdk.org
>> Subject: Re: [dpdk-dev] [PATCH 0/4] DPDK memcpy optimization
>>
>> 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@tuxdriver.com]
>>>>> Sent: Monday, January 19, 2015 9:02 PM
>>>>> To: Wang, Zhihong
>>>>> Cc: dev@dpdk.org
>>>>> Subject: Re: [dpdk-dev] [PATCH 0/4] DPDK memcpy optimization
>>>>>
>>>>> On Mon, Jan 19, 2015 at 09:53:30AM +0800, zhihong.wang@intel.com
>> 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
> Neil, Bruce,
>
> Some data first.
>
> Sandy Bridge without AVX2:
> 1. original w/ 10 constant memcpy: 2'25"
> 2. patch w/ 12 constant memcpy: 2'41"
> 3. patch w/ 63 constant memcpy: 9'41"
>
> Haswell with AVX2:
> 1. original w/ 10 constant memcpy: 1'57"
> 2. patch w/ 12 constant memcpy: 1'56"
> 3. patch w/ 63 constant memcpy: 3'16"
>
> Also, to address Bruce's question, we have to reduce test case to cut down compile time. Because we use:
> 1. intrinsics instead of assembly for better flexibility and can utilize more compiler optimization
> 2. complex function body for better performance
> 3. inlining
> This increases compile time.
> But I think it'd be okay to do that as long as we can select a fair set of test points.
>
> It'd be great if you could give some suggestion, say, 12 points.
>
> Zhihong (John)
>
>
While I agree in the general case these long compilation times is
painful for the users, having a factor of 2-8x in memcpy operations is
quite an improvement, specially in DPDK applications which need to deal
(unfortunately) heavily on them -- e.g. IP fragmentation and reassembly.
Why not having a fast compilation by default, and a tunable config flag
to enable a highly optimized version of rte_memcpy (e.g.
RTE_EAL_OPT_MEMCPY)?
Marc
>
next prev parent reply other threads:[~2015-01-21 12:36 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-01-19 1:53 zhihong.wang
2015-01-19 1:53 ` [dpdk-dev] [PATCH 1/4] app/test: Disabled VTA for memcpy test in app/test/Makefile zhihong.wang
2015-01-19 1:53 ` [dpdk-dev] [PATCH 2/4] app/test: Removed unnecessary test cases in test_memcpy.c zhihong.wang
2015-01-19 1:53 ` [dpdk-dev] [PATCH 3/4] app/test: Extended test coverage in test_memcpy_perf.c zhihong.wang
2015-01-19 1:53 ` [dpdk-dev] [PATCH 4/4] lib/librte_eal: Optimized memcpy in arch/x86/rte_memcpy.h for both SSE and AVX platforms zhihong.wang
2015-01-20 17:15 ` Stephen Hemminger
2015-01-20 19:16 ` Neil Horman
2015-01-21 3:18 ` Wang, Zhihong
2015-01-25 20:02 ` Jim Thompson
2015-01-26 14:43 ` Wodkowski, PawelX
2015-01-27 5:12 ` Wang, Zhihong
2015-01-19 13:02 ` [dpdk-dev] [PATCH 0/4] DPDK memcpy optimization Neil Horman
2015-01-20 3:01 ` Wang, Zhihong
2015-01-20 15:11 ` Neil Horman
2015-01-20 16:14 ` Bruce Richardson
2015-01-21 3:44 ` Wang, Zhihong
2015-01-21 11:40 ` Bruce Richardson
2015-01-21 12:02 ` Ananyev, Konstantin
2015-01-21 12:38 ` Neil Horman
2015-01-23 3:26 ` Wang, Zhihong
2015-01-21 12:36 ` Marc Sune [this message]
2015-01-21 13:02 ` Bruce Richardson
2015-01-21 13:21 ` Marc Sune
2015-01-21 13:26 ` Bruce Richardson
2015-01-21 19:49 ` Stephen Hemminger
2015-01-21 20:54 ` Neil Horman
2015-01-21 21:25 ` Jim Thompson
2015-01-22 0:53 ` Stephen Hemminger
2015-01-22 9:06 ` Luke Gorrie
2015-01-22 13:29 ` Jay Rolette
2015-01-22 18:27 ` Luke Gorrie
2015-01-22 19:36 ` Jay Rolette
2015-01-22 18:21 ` EDMISON, Kelvin (Kelvin)
2015-01-27 8:22 ` Wang, Zhihong
2015-01-28 21:48 ` EDMISON, Kelvin (Kelvin)
2015-01-29 1:53 ` Wang, Zhihong
2015-01-23 6:52 ` Wang, Zhihong
2015-01-26 18:29 ` Ananyev, Konstantin
2015-01-27 1:42 ` Wang, Zhihong
2015-01-27 11:30 ` Ananyev, Konstantin
2015-01-27 12:19 ` Ananyev, Konstantin
2015-01-28 2:06 ` Wang, Zhihong
2015-01-25 14:50 ` Luke Gorrie
2015-01-26 1:30 ` Wang, Zhihong
2015-01-26 8:03 ` Luke Gorrie
2015-01-27 7:19 ` Wang, Zhihong
2015-01-27 13:57 ` [dpdk-dev] [snabb-devel] " Luke Gorrie
2015-01-29 3:42 ` [dpdk-dev] " Fu, JingguoX
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