how to replace memcpy with neon based on memcpy?

SuitJune Young

Genius 3985 points

If I want to replace memcpy of linux with NEON based memcpy for a faster operation,how to do?

Need to change complier options?Or something else?

thanks for any reply.

over 11 years ago

0 Badri Narayanan over 11 years ago

TI__Guru 59700 points

DVR RDK 4.0 includes functions for neon optimized memcpy. The function is called memcpy_neon and has same signature as memcpy. You can use it from user space code by explicity calling memcpy_neon where required. memcpy_neon is beneficial only for large memory copies .Pls see this article from for details of using neon based memcpy which is adopted in dvr rdk 4.0

http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.faqs/ka13544.html

0 Pierre-Louis Cabelguen over 11 years ago

Prodigy 150 points

Hi !

First you will need to compile memcpy_neon as a .so file.

Then use LD_PRELOAD=/path/to/your/memcpy_neon.so in your environment. This will ensure all memcpy() calls use the optimized version.

Regards.

0 Yogesh Marathe over 11 years ago in reply to Pierre-Louis Cabelguen

TI__Expert 7765 points

After you install NVRSOURCE_04.00.00.03.tar.lzma package you will see DVRRDK_04.00.00.03/dvr_rdk/module/memcpy_neon folder which you can use as it is in your application.

0 SuitJune Young over 11 years ago in reply to Yogesh Marathe

Genius 3985 points

thank all of you! I will try that.

0 SuitJune Young over 11 years ago in reply to Yogesh Marathe

Genius 3985 points

Can I just replace memcpy_neos.S with memcpy.s in dvrrdk_03.00.00.00/ti_tools/linux_lsp/linux-psp-dvr-04.04.00.01/src/linux_04.04.00.01/arch/arm/lib/memcpy.s?

0 Badri Narayanan over 11 years ago in reply to SuitJune Young

TI__Guru 59700 points

No you cannot use neon instructions in kernel space. The LD_PRELOAD suggested by Pierre above is the preferred method and can be used only for user space code.

0 1330hayacool7102 over 10 years ago in reply to Yogesh Marathe

Guru 10655 points

hello Yogesh,

Yogesh Marathe said:

After you install NVRSOURCE_04.00.00.03.tar.lzma package you will see DVRRDK_04.00.00.03/dvr_rdk/module/memcpy_neon folder which you can use as it is in your application.

by following, we found nothing about memcpy_neon. Do I mis-understand ?

[/areaX/DVRRDK_04.00.00.03/DVRRDK_04.00.00.03] $ find ./dvr_rdk/ -type f -name "memcpy_neon"
[/areaX/DVRRDK_04.00.00.03/DVRRDK_04.00.00.03] $

0 shawnstone over 10 years ago

Intellectual 850 points

Hi,Young

When I install NVRSOURCE_04.00.00.03.tar.lzma package ，it says the data of package is broken，can you give a copy of NVRSOURCE_04.00.00.03.tar.lzma package

my email : xiaodeo@126.com

thank a lot!

regards

shawn

0 user4319074 over 9 years ago in reply to shawnstone

Prodigy 140 points

my NVRSOURCE_04.00.00.03.tar.lzma package is broken too. can you give me a copy. my email is coolpeng68@163.com

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how to replace memcpy with neon based on memcpy?