61 lines
2.0 KiB
C++
61 lines
2.0 KiB
C++
// http://www.apache.org/licenses/LICENSE-2.0
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// Copyright 2014 Perttu Ahola <celeron55@gmail.com>
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#pragma once
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#include <functional>
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#include <cstring> // memset()
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#include <unistd.h> // usleep()
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#include "os.h" // get_timeofday_us()
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#include "log.h"
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// If f() returns false, loop ends
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void interval_loop(int interval_us, std::function<bool(float load_avg)> f)
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{
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int64_t t_scheduled_tick_start = get_timeofday_us();
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t_scheduled_tick_start /= interval_us; // Align to round numbers
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t_scheduled_tick_start *= interval_us;
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float load_sum = 0;
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const int load_avg_length = interval_us < 500000 ? 5000000 / interval_us : 1;
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float *load_log = new float[load_avg_length];
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memset(load_log, 0, sizeof(float) * load_avg_length);
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int load_log_i = load_avg_length - 1;
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float last_load_avg = 0;
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for(;;){
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int64_t t_now = get_timeofday_us();
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t_scheduled_tick_start += interval_us;
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int64_t t_until_next_tick = t_scheduled_tick_start - t_now;
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if(t_until_next_tick < 0 || t_until_next_tick > interval_us){
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log_w("loop", "interval_loop(): Delayed by %" PRId64 "ms"
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" (%+.0f%% interval)", -t_until_next_tick / 1000,
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-100.0 * t_until_next_tick / interval_us);
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// Give up if off by too much (100ms)
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if(t_scheduled_tick_start < t_now - 100000){
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t_scheduled_tick_start = t_now;
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t_until_next_tick = 0;
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}
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}
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if(t_until_next_tick > 0)
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usleep(t_until_next_tick);
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int64_t t_tick_start = get_timeofday_us();
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//log_i("loop", "t_tick_start=%" PRId64, t_tick_start);
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if(!f(last_load_avg))
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break;
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int64_t t_tick_end = get_timeofday_us();
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int64_t t_tick_length = t_tick_end > t_tick_start ? t_tick_end -
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t_tick_start : 0;
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float load_ratio = (float)t_tick_length / interval_us;
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//log_i("loop", "load_ratio=%f", load_ratio);
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load_log[load_log_i] = load_ratio;
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load_sum += load_log[load_log_i];
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load_log_i = (load_log_i + 1) % load_avg_length;
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float load_avg = load_sum / load_avg_length;
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//log_i("loop", "load_avg=%f", load_avg);
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last_load_avg = load_avg;
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load_sum -= load_log[load_log_i];
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}
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delete[] load_log;
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}
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// vim: set noet ts=4 sw=4:
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