topic Re: Measure execution time (MQX 4.1) in MQX Software Solutions

Measure execution time (MQX 4.1)

michael_wahler — Tue, 06 Jan 2015 15:32:46 GMT

Hi,

What is the best way of measuring the execution time of a function with nanosecond precision on MQX 4.1?

What I have in mind is something like

uint32_t start = get_time ();

f();

uint32_t delta = get_time () - start;

However, _time_get_nanoseconds () does not work for me because there is a timer interrupt during the execution of f().

Any ideas?

Regards,

Michael

Re: Measure execution time (MQX 4.1)

DavidS — Tue, 06 Jan 2015 22:55:15 GMT

Hi Michael,

I think using the timeget_elapsed_ticks() function would work as it has the number of TICKS (5 msec) in a 64-bit variable since the beginning of MQX execution as well as a HWTICKS variable which is the number of hardware ticks that have occurred since the last TICK.

Calling it before and after your f(); should give you the time.

Please also look at this post:

https://community.freescale.com/thread/334266

Hope this helps.

Regards,

David

Re: Measure execution time (MQX 4.1)

michael_wahler — Wed, 07 Jan 2015 08:40:00 GMT

Hi David,

Thank you for your response. Unfortunately, the resolution of your solution is only 5 milliseconds whereas I need microsecond (or better, nanosecond) precision.

Kind regards

Michael

Re: Measure execution time (MQX 4.1)

soledad — Thu, 08 Jan 2015 17:23:11 GMT

Hi Michael,

Please check the below thread

Change MQX periodic timer period?

Have a great day,
Sol

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Re: Measure execution time (MQX 4.1)

michaelzhangca — Thu, 08 Jan 2015 18:16:32 GMT

If possible, you could try to set a IO pin high before execute the funtion, set to low after the function. Use scope to measure the IO pin, this is the way I used.

Re: Re: Measure execution time (MQX 4.1)

DavidS — Thu, 08 Jan 2015 18:20:15 GMT

Hi Michael,

Please have a look at my modified lwevent project source code attached to see if this resolves your issue.

My terminal output looks like:

Tick

0Min:1Sec:999ms:998751us:998750808ns

Tick

0Min:2Sec:2217ms:2216541us:2216541475ns

Tick

0Min:2Sec:2771ms:2771294us:2771293975ns

Tick

0Min:3Sec:3326ms:3326289us:3326289333ns

Tick

0Min:1Sec:1661ms:1661286us:1661285900ns

Tick

0Min:3Sec:3881ms:3881293us:3881292742ns

Tick

0Min:0Sec:551ms:551269us:551269458ns

Tick

0Min:4Sec:4437ms:4436523us:141555812ns

Tick

0Min:1Sec:1106ms:1106352us:1106351800ns

Tick

0Min:4Sec:4991ms:4991266us:696298787ns

Tick

0Min:0Sec:996ms:996351us:996350950ns

Regards,

David