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3fb6a7b46e
The new sched_activity structure will be used to collect task-level
activity based on the target function. The principle is to declare a
large enough array to make collisions rare (256 entries), and hash
the function pointer using a reduced XXH to decide where to store the
stats. On first computation an entry is definitely assigned to the
array and it's done atomically. A special entry (0) is used to store
collisions ("others"). The goal is to make it easy and inexpensive for
the scheduler code to use these to store #calls, cpu_time and lat_time
for each task.
127 lines
4.1 KiB
C
127 lines
4.1 KiB
C
/*
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* include/haproxy/activity.h
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* This file contains macros and inline functions for activity measurements.
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*
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* Copyright (C) 2000-2020 Willy Tarreau - w@1wt.eu
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation, version 2.1
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* exclusively.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#ifndef _HAPROXY_ACTIVITY_H
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#define _HAPROXY_ACTIVITY_H
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#include <import/xxhash.h>
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#include <haproxy/activity-t.h>
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#include <haproxy/api.h>
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#include <haproxy/freq_ctr.h>
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#include <haproxy/time.h>
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extern unsigned int profiling;
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extern unsigned long task_profiling_mask;
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extern struct activity activity[MAX_THREADS];
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extern struct sched_activity sched_activity[256];
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void report_stolen_time(uint64_t stolen);
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/* Collect date and time information before calling poll(). This will be used
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* to count the run time of the past loop and the sleep time of the next poll.
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* It also makes use of the just updated before_poll timer to count the loop's
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* run time and feed the average loop time metric (in microseconds).
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*/
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static inline void activity_count_runtime()
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{
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uint64_t new_mono_time;
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uint64_t new_cpu_time;
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int64_t stolen;
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uint32_t run_time;
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uint32_t up, down;
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/* 1 millisecond per loop on average over last 1024 iterations is
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* enough to turn on profiling.
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*/
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up = 1000;
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down = up * 99 / 100;
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new_cpu_time = now_cpu_time();
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new_mono_time = now_mono_time();
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if (ti->prev_cpu_time && ti->prev_mono_time) {
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new_cpu_time -= ti->prev_cpu_time;
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new_mono_time -= ti->prev_mono_time;
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stolen = new_mono_time - new_cpu_time;
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if (unlikely(stolen >= 500000)) {
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stolen /= 500000;
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/* more than half a millisecond difference might
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* indicate an undesired preemption.
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*/
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report_stolen_time(stolen);
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}
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}
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run_time = (before_poll.tv_sec - after_poll.tv_sec) * 1000000U + (before_poll.tv_usec - after_poll.tv_usec);
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run_time = swrate_add(&activity[tid].avg_loop_us, TIME_STATS_SAMPLES, run_time);
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/* In automatic mode, reaching the "up" threshold on average switches
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* profiling to "on" when automatic, and going back below the "down"
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* threshold switches to off. The forced modes don't check the load.
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*/
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if (!(task_profiling_mask & tid_bit)) {
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if (unlikely((profiling & HA_PROF_TASKS_MASK) == HA_PROF_TASKS_ON ||
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((profiling & HA_PROF_TASKS_MASK) == HA_PROF_TASKS_AON &&
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swrate_avg(run_time, TIME_STATS_SAMPLES) >= up)))
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_HA_ATOMIC_OR(&task_profiling_mask, tid_bit);
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} else {
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if (unlikely((profiling & HA_PROF_TASKS_MASK) == HA_PROF_TASKS_OFF ||
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((profiling & HA_PROF_TASKS_MASK) == HA_PROF_TASKS_AOFF &&
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swrate_avg(run_time, TIME_STATS_SAMPLES) <= down)))
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_HA_ATOMIC_AND(&task_profiling_mask, ~tid_bit);
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}
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}
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/* Computes the index of function pointer <func> for use with sched_activity[]
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* or any other similar array passed in <array>, and returns a pointer to the
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* entry after having atomically assigned it to this function pointer. Note
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* that in case of collision, the first entry is returned instead ("other").
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*/
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static inline struct sched_activity *sched_activity_entry(struct sched_activity *array, const void *func)
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{
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uint64_t hash = XXH64_avalanche(XXH64_mergeRound((size_t)func, (size_t)func));
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struct sched_activity *ret;
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const void *old = NULL;
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hash ^= (hash >> 32);
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hash ^= (hash >> 16);
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hash ^= (hash >> 8);
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hash &= 0xff;
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ret = &array[hash];
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if (likely(ret->func == func))
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return ret;
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if (HA_ATOMIC_CAS(&ret->func, &old, func))
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return ret;
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return array;
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}
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#endif /* _HAPROXY_ACTIVITY_H */
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/*
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* Local variables:
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* c-indent-level: 8
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* c-basic-offset: 8
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* End:
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*/
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