1 | /** |
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2 | * @file |
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3 | * |
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4 | * @ingroup or1ksim |
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5 | * |
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6 | * @brief Benchmark timer support. |
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7 | */ |
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8 | |
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9 | /* |
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10 | * Copyright (c) 2014 by Hesham ALMatary |
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11 | * |
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12 | * The license and distribution terms for this file may be |
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13 | * found in the file LICENSE in this distribution or at |
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14 | * http://www.rtems.org/license/LICENSE |
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15 | */ |
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16 | |
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17 | #include <rtems.h> |
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18 | #include <rtems/btimer.h> |
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19 | #include <bsp/or1ksim.h> |
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20 | #include <rtems/score/or1k-utility.h> |
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21 | |
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22 | #define OR1KSIM_NANOSECONDS_PER_CLK_CYCLE 10 |
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23 | |
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24 | static bool benchmark_timer_find_average_overhead = false; |
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25 | static uint64_t benchmark_timer_base; |
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26 | |
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27 | void benchmark_timer_initialize(void) |
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28 | { |
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29 | benchmark_timer_base = _OR1K_mfspr(CPU_OR1K_SPR_TTCR); |
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30 | } |
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31 | |
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32 | #define AVG_OVERHEAD 0 |
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33 | #define LEAST_VALID 1 |
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34 | |
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35 | uint32_t benchmark_timer_read( void ) |
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36 | { |
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37 | uint64_t clicks; |
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38 | uint64_t total; |
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39 | uint64_t delta; |
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40 | /* |
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41 | * Read the timer and see how many clicks (clock cycles) |
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42 | * has passed since timer initialization. |
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43 | */ |
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44 | clicks = _OR1K_mfspr(CPU_OR1K_SPR_TTCR); |
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45 | |
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46 | delta = clicks - benchmark_timer_base; |
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47 | |
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48 | /* total in nanoseconds */ |
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49 | total = OR1KSIM_NANOSECONDS_PER_CLK_CYCLE * (delta); |
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50 | |
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51 | if ( benchmark_timer_find_average_overhead == true ) |
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52 | return total; /* in nanoseconds microsecond units */ |
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53 | else { |
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54 | if ( total < LEAST_VALID ) |
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55 | return 0; /* below timer resolution */ |
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56 | |
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57 | return (total - AVG_OVERHEAD); |
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58 | } |
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59 | } |
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60 | |
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61 | void benchmark_timer_disable_subtracting_average_overhead(bool find_flag) |
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62 | { |
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63 | benchmark_timer_find_average_overhead = find_flag; |
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64 | } |
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