Michael Chuah / Mbed 2 deprecated Benchmark

Benchmarking test code for various operations

Dependencies:   mbed

Fork of benchmark by Igor Martinovski

Benchmarking the performance of various mbed boards that I have

Using the excellent code by Igor, I have benchmarked the performance of the following platforms:

The data can be found in this link: https://docs.google.com/spreadsheets/d/1d5BcNvC341xvktRJ6DC3wdlI6wuv0FjCvCqHAnfINmQ/pubhtml

For the hyperbolic tan (tanh) function, I made a graph showing how the clock speed of various ARM Cortex-M4 boards with FPU affects the computation time in microseconds. Computation Time - tanh

main.cpp@3:ec2e20a9bd03, 2017-02-28 (annotated)

Committer:
mcx
Date:
Tue Feb 28 20:54:35 2017 +0000
Revision:
3:ec2e20a9bd03
Parent:
2:fc68d524dd7d 
Now prints out clock speed in MHz

Who changed what in which revision?

UserRevisionLine numberNew contents of line
igor_m 0:6d89d8c13042 1 #include "mbed.h"
mcx 1:f91e7bc0e244 2
mcx 1:f91e7bc0e244 3 //https://developer.mbed.org/users/igor_m/code/benchmark/
igor_m 0:6d89d8c13042 4 /* This program determines the time it takes to perform floating point
igor_m 0:6d89d8c13042 5 and integer operations.
igor_m 0:6d89d8c13042 6 To determine the time it takes, a Timer is used to measure the time
igor_m 0:6d89d8c13042 7 it takes to complete a large amount of iterations. The time for a single
igor_m 0:6d89d8c13042 8 operation can then be determined.
igor_m 0:6d89d8c13042 9
igor_m 0:6d89d8c13042 10 To increase accuracy of the results, an empty for loop is timed to determine
igor_m 0:6d89d8c13042 11 the loop overhead and the overhead is subtracted from the time it takes to
igor_m 0:6d89d8c13042 12 complete the operation loop.
mcx 1:f91e7bc0e244 13 */
igor_m 0:6d89d8c13042 14
igor_m 0:6d89d8c13042 15 #define ITERATIONS 1000000 // Number of calculations.
mcx 3:ec2e20a9bd03 16 #define CLOCK 64 // Clock freqency in MHz
igor_m 0:6d89d8c13042 17 Timer timer; // Timer..
igor_m 0:6d89d8c13042 18
igor_m 0:6d89d8c13042 19 Serial pc(USBTX, USBRX);
igor_m 0:6d89d8c13042 20 float number_of_cycles, single_operation_time;
mcx 3:ec2e20a9bd03 21 //volatile int a, b, c; // Int operands and result. Must be volatile!
mcx 3:ec2e20a9bd03 22 volatile float a, b, c; // Float operands and result. Must be volatile!
mcx 1:f91e7bc0e244 23 //volatile double a, b, c; // Float operands and result. Must be volatile!
igor_m 0:6d89d8c13042 24
igor_m 0:6d89d8c13042 25 int main() {
igor_m 0:6d89d8c13042 26
mcx 3:ec2e20a9bd03 27 // Apparently I'm not getting full speed!?
mcx 3:ec2e20a9bd03 28 // https://developer.mbed.org/forum/mbed/topic/229/?page=1
mcx 3:ec2e20a9bd03 29 // https://developer.mbed.org/questions/55557/CPU-clock-of-upto-100MHz/
mcx 3:ec2e20a9bd03 30 printf("SystemCoreClock = %d MHz\r\n", SystemCoreClock/1000000);
mcx 3:ec2e20a9bd03 31 // Need external crystal to make it run faster?
mcx 3:ec2e20a9bd03 32 // https://developer.mbed.org/users/dreschpe/code/ST_401_84MHZ/
mcx 3:ec2e20a9bd03 33 // https://developer.mbed.org/users/oliverb/notebook/crystal-oscillator-notes/
mcx 3:ec2e20a9bd03 34
igor_m 0:6d89d8c13042 35 unsigned int i, for_time, total_time, operation_time;
igor_m 0:6d89d8c13042 36 a=2.3;
igor_m 0:6d89d8c13042 37 b=5.33;
igor_m 0:6d89d8c13042 38
igor_m 0:6d89d8c13042 39 timer.reset(); // Reset timer
igor_m 0:6d89d8c13042 40 timer.start(); // Start timer
mcx 1:f91e7bc0e244 41 pc.printf("Operations in progress.. May take some time.\r\n");
igor_m 0:6d89d8c13042 42 /* Determine loop overhead */
mcx 1:f91e7bc0e244 43 for (i=0; i<ITERATIONS; i++){}
igor_m 0:6d89d8c13042 44 for_time=timer.read_us();
igor_m 0:6d89d8c13042 45 timer.stop();
igor_m 0:6d89d8c13042 46
igor_m 0:6d89d8c13042 47 /* Determine the total loop time */
igor_m 0:6d89d8c13042 48 timer.reset();
igor_m 0:6d89d8c13042 49 timer.start();
igor_m 0:6d89d8c13042 50
igor_m 0:6d89d8c13042 51 /* The operation takes place in the body of
igor_m 0:6d89d8c13042 52 this for loop. */
mcx 1:f91e7bc0e244 53 for (i=0; i<ITERATIONS; i++){
igor_m 0:6d89d8c13042 54
mcx 3:ec2e20a9bd03 55 // a = b;
mcx 1:f91e7bc0e244 56 // c = a+b;
mcx 1:f91e7bc0e244 57 // c = a*b;
mcx 1:f91e7bc0e244 58 // c = a/b;
mcx 1:f91e7bc0e244 59 // a = sqrt(b);
mcx 1:f91e7bc0e244 60 // a = log(b);
mcx 1:f91e7bc0e244 61 // a = tanh(b);
mcx 3:ec2e20a9bd03 62 // a = (10*pow(b,3) + 105*b)/(pow(b,4) + 45*pow(b,2) + 105);
mcx 3:ec2e20a9bd03 63 a = (10*b*b*b + 105*b)/(b*b*b*b + 45* + 105);
igor_m 0:6d89d8c13042 64 }
mcx 1:f91e7bc0e244 65
igor_m 0:6d89d8c13042 66 total_time=timer.read_us();
igor_m 0:6d89d8c13042 67
igor_m 0:6d89d8c13042 68 operation_time = total_time-for_time; // Calculate the time it took for the number of operations
igor_m 0:6d89d8c13042 69
igor_m 0:6d89d8c13042 70 single_operation_time=float(operation_time)/float(ITERATIONS);
igor_m 0:6d89d8c13042 71 number_of_cycles = single_operation_time*CLOCK;
igor_m 0:6d89d8c13042 72
mcx 1:f91e7bc0e244 73 pc.printf("for overhead: \t\t%dus \r\n", for_time);
mcx 1:f91e7bc0e244 74 pc.printf("total time: \t\t%dus \r\n", total_time);
mcx 1:f91e7bc0e244 75 pc.printf("%d calculations took:\t%dus \r\n", ITERATIONS, operation_time);
mcx 1:f91e7bc0e244 76 pc.printf("single operation took: \t\t%fus \r\n", single_operation_time);
mcx 1:f91e7bc0e244 77 pc.printf("single operation took: \t\t%.3f cycles \r\n", number_of_cycles);
igor_m 0:6d89d8c13042 78 }