AM3358: CPU usage

May

Part Number: AM3358

Hi Team,

Customer want to know how to reduce CPU usage when sending 3.5kb per second in the UART and baudrate is 115200

According to the customer, they make one application for data transfer serial to TCP but while running the CPU usage is high.

Thank you.

Regards,

Maynard

over 4 years ago

0 Bin Liu over 4 years ago

TI__Guru**** 174421 points

Hi Maynard,

What OS is used? TI Processor SDK Linux or RTOS?

0 May over 4 years ago in reply to Bin Liu

TI__Genius 9880 points

Hi Bin,

Apologies for the late response.

The customer is using TI Processor SDK Linux. version - ti-processor-sdk-linux-am335x-evm-06.01.00.08

Regards,

Maynard

0 Bin Liu over 4 years ago in reply to May

TI__Guru**** 174421 points

Hi Maynard,

Has the customer done any analysis to understand which portion of the program execution causes the high CPU usage?

0 Bin Liu over 4 years ago in reply to May

TI__Guru**** 174421 points

Any which UART port is used? Is EDMA enabled for this UART port?

0 May over 4 years ago in reply to Bin Liu

TI__Genius 9880 points

Hi Bin,

Below is the customer response.

1. We did some analysis on that when sending single byte using while loop in any serial port also cpu usage goes upto 60 to 80 percentage

2. Our application needs 12 serial port so we used 4 native UART and 2 usb to quad UART converter. We tested all 12 serial port it's shows same issue. We are not did any changes in kernel and we used default zimage only.

For transfering data in serial port to TCP socket we used ser2sock application which is got it from github. Pls find the source file link below

https://github.com/nutechsoftware/ser2sock/blob/master/ser2sock.c

Regards,

Maynard

0 Bin Liu over 4 years ago in reply to May

TI__Guru**** 174421 points

Hi Maynard,

I am unable to reproduce the issue.

I enabled UART1 in Beaglebone Black board devicetree, and rebuilt the kernel in Processor SDK Linux v6.3, and run the following command to transmit a single byte using a while loop to UART1 in 115200 baud rate, I barely see CPU load change. Please ask the customer to do further analysis to understand which program in their system causes the high CPU load.

root@am335x-evm:~# stty -F /dev/ttyS1 -echo 115200
root@am335x-evm:~# while true; do echo 'a' > /dev/ttyS1; done

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AM3358: CPU usage