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@1:f91e7bc0e244, 2015-08-17 (annotated)

Committer:
mcx
Date:
Mon Aug 17 20:14:39 2015 +0000
Revision:
1:f91e7bc0e244
Parent:
0:6d89d8c13042
Child:
2:fc68d524dd7d
Benchmarking code to test speed of various operations;

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 1:f91e7bc0e244 16 #define CLOCK 100 // 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 1:f91e7bc0e244 21 //volatile int a, b, c; // Int operands and result. Must be volatile!
mcx 1:f91e7bc0e244 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
igor_m 0:6d89d8c13042 27 unsigned int i, for_time, total_time, operation_time;
igor_m 0:6d89d8c13042 28 a=2.3;
igor_m 0:6d89d8c13042 29 b=5.33;
igor_m 0:6d89d8c13042 30
igor_m 0:6d89d8c13042 31 timer.reset(); // Reset timer
igor_m 0:6d89d8c13042 32 timer.start(); // Start timer
mcx 1:f91e7bc0e244 33 pc.printf("Operations in progress.. May take some time.\r\n");
igor_m 0:6d89d8c13042 34 /* Determine loop overhead */
mcx 1:f91e7bc0e244 35 for (i=0; i<ITERATIONS; i++){}
igor_m 0:6d89d8c13042 36 for_time=timer.read_us();
igor_m 0:6d89d8c13042 37 timer.stop();
igor_m 0:6d89d8c13042 38
igor_m 0:6d89d8c13042 39 /* Determine the total loop time */
igor_m 0:6d89d8c13042 40 timer.reset();
igor_m 0:6d89d8c13042 41 timer.start();
igor_m 0:6d89d8c13042 42
igor_m 0:6d89d8c13042 43 /* The operation takes place in the body of
igor_m 0:6d89d8c13042 44 this for loop. */
mcx 1:f91e7bc0e244 45 for (i=0; i<ITERATIONS; i++){
igor_m 0:6d89d8c13042 46
mcx 1:f91e7bc0e244 47 // a = b;
mcx 1:f91e7bc0e244 48 // c = a+b;
mcx 1:f91e7bc0e244 49 // c = a*b;
mcx 1:f91e7bc0e244 50 // c = a/b;
mcx 1:f91e7bc0e244 51 // a = sqrt(b);
mcx 1:f91e7bc0e244 52 // a = log(b);
mcx 1:f91e7bc0e244 53 // a = tanh(b);
igor_m 0:6d89d8c13042 54
igor_m 0:6d89d8c13042 55 }
mcx 1:f91e7bc0e244 56
igor_m 0:6d89d8c13042 57 total_time=timer.read_us();
igor_m 0:6d89d8c13042 58
igor_m 0:6d89d8c13042 59 operation_time = total_time-for_time; // Calculate the time it took for the number of operations
igor_m 0:6d89d8c13042 60
igor_m 0:6d89d8c13042 61 single_operation_time=float(operation_time)/float(ITERATIONS);
igor_m 0:6d89d8c13042 62 number_of_cycles = single_operation_time*CLOCK;
igor_m 0:6d89d8c13042 63
mcx 1:f91e7bc0e244 64 pc.printf("for overhead: \t\t%dus \r\n", for_time);
mcx 1:f91e7bc0e244 65 pc.printf("total time: \t\t%dus \r\n", total_time);
mcx 1:f91e7bc0e244 66 pc.printf("%d calculations took:\t%dus \r\n", ITERATIONS, operation_time);
mcx 1:f91e7bc0e244 67 pc.printf("single operation took: \t\t%fus \r\n", single_operation_time);
mcx 1:f91e7bc0e244 68 pc.printf("single operation took: \t\t%.3f cycles \r\n", number_of_cycles);
igor_m 0:6d89d8c13042 69 }