What is the maximum transmission interprocessor bandwidth on STM32MP1?

Forum|Forum|6 years ago
May 10, 2019
2 replies
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I am interested in the maximum transmission bandwidth between the A7 core and M4 core on the STM32MP1.

I did some test using RPMsg framewirk and sent messages with length 496 Byte from the A7 core to the M4 core. Therefore I modified the OpenAMP_raw example. I measured the time which it takes to receive 2300 messages on the M4 side using HAL_getTick(). I measured an average time of 132 ms, which would result in a transmission bandwidth of just 8,64 MB/s, which seems pretty slow to me.

Has anyone made some experience with it or did some similar evaluation? Maybe me measurement method isnt optimal? I am thankful for evey opinion.

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Best answer by Olivier GALLIEN

Hi @robsen223

Could you please confirm data you provided ?

Computing given data we found 8,6MB/s ( 2300*496/0.132)

For your information, in an dedicated optimized environment we achieved 15.4MB/s (512 Bytes buffer size).

But this is really dependent of context on both cores and application.

Else generally speaking bandwidth can be enhanced :

by increasing RPMSG Buffer size, but till a reasonable limit (eg 2048) since RPMSG is designed for message (control ) and not data.
by using a shared memory ( rpmsg used for pointers exchange between cores)

BR,

Olivier

O

Olivier GALLIENAnswer

Technical Moderator

Hi @robsen223

Could you please confirm data you provided ?

Computing given data we found 8,6MB/s ( 2300*496/0.132)

For your information, in an dedicated optimized environment we achieved 15.4MB/s (512 Bytes buffer size).

But this is really dependent of context on both cores and application.

Else generally speaking bandwidth can be enhanced :

by increasing RPMSG Buffer size, but till a reasonable limit (eg 2048) since RPMSG is designed for message (control ) and not data.
by using a shared memory ( rpmsg used for pointers exchange between cores)

BR,

Olivier

R

robsen223Author

Visitor II

Hi @Community member

you are absolutely right with 8,6MB/s. I mixed up my notes.

Thank you for your comments. It gave my the right food of thought and helped me to finish my work. Especially I thought that RPMsg is the only option for data transmisson. I really like the idea of sending just pointer through RPMsg.