BF537 performance measurements

Customized kernel image created in previous post provides a way to measure execution / performance time. It could be done with help of oscilloscope connected to the boards ground and LED connections. Application pflags-test is executed in user space of uClinux and is using GPIO driver to enable button and LEDs processing. Code below shows in comments measured with oscilloscope execution time.

    write(fd0,"0",sizeof("0"));    // 16 microseconds
    usleep(1000);                      //   4 milliseconds
    write(fd0,"1",sizeof("1"));    // 16 microseconds
    usleep(1000);                      //   4 milliseconds

Arithmetic operations could be tested with help of cycle. This will allow having sufficient amount of time to measure as shown in the code:

    long a, c, i = 0;
    for( i = 0; i < 100000; i++)
    {
         c = i + a;
    }
    printtime();

This time measurements were done with help of system time functions and results are presented in table below.

Operation	Cycle Number	Variable Type	Time
+	100000	long	4 ms
+	1000000	long	45 ms
*	100000	long	6 ms
*	1000000	long	48 ms
+	100000	float	107 ms
+	1000000	float	1061 ms
*	100000	float	89 ms
*	1000000	float	887 ms

Trigonometric functions measurements could be done with adding in C file #include <math.h>, and option "-lm" to the linker command. Review previous post on details of how to configure blackfin toolkit for uClinux program compilation.

bfin-uclinux-gcc -Wl,-elf2flt perftest.c -o perftest -lm

Operation	Cycle Number	Variable Type	Time
cos	100000	long	6268 ms
cos	1000000	long	62681 ms