switch_profile.c

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/*
 * Copyright (c) 2009, Sangoma Technologies
 * Moises Silva <moy@sangoma.com>
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 
 * * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 * 
 * * Redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution.
 * 
 * * Neither the name of the original author; nor the names of any contributors
 * may be used to endorse or promote products derived from this software
 * without specific prior written permission.
 * 
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER
 * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
#include "switch.h"
#include "private/switch_core_pvt.h"

#ifdef __linux__
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <fcntl.h>
#include <errno.h>
#endif

struct profile_timer 
{
        /* bool, just used to retrieve the values for the first time and not calculate the percentage of idle time */
        int valid_last_times;

        /* last calculated percentage of idle time */
        double last_percentage_of_idle_time;
        double *percentage_of_idle_time_ring;
        unsigned int last_idle_time_index;
        unsigned int cpu_idle_smoothing_depth;

#ifdef __linux__
        /* the cpu feature gets disabled on errors */
        int disabled;
        /* all of these are the Linux jiffies last retrieved count */
        unsigned long long last_user_time;
        unsigned long long last_system_time;
        unsigned long long last_idle_time;

        unsigned long long last_nice_time;
        unsigned long long last_irq_time;
        unsigned long long last_soft_irq_time;
        unsigned long long last_io_wait_time;
        unsigned long long last_steal_time;

        /* /proc/stat file descriptor used to retrieve the counters */
        int procfd;
        int initd;
#elif defined (WIN32)  || defined (WIN64)
        __int64 i64LastUserTime;
        __int64 i64LastKernelTime;
        __int64 i64LastIdleTime;
#else
  /* Unsupported */
#endif
};

#ifdef __linux__
static int read_cpu_stats(switch_profile_timer_t *p, 
                unsigned long long *user, 
                unsigned long long *nice, 
                unsigned long long *system, 
                unsigned long long *idle, 
                unsigned long long *iowait, 
                unsigned long long *irq, 
                unsigned long long *softirq, 
                unsigned long long *steal)
{
// the output of proc should not change that often from one kernel to other
// see fs/proc/proc_misc.c or fs/proc/stat.c in the Linux kernel for more details
// also man 5 proc is useful.
#define CPU_ELEMENTS_1 7 // change this if you change the format string
#define CPU_INFO_FORMAT_1 "cpu  %llu %llu %llu %llu %llu %llu %llu"

#define CPU_ELEMENTS_2 8 // change this if you change the format string
#define CPU_INFO_FORMAT_2 "cpu  %llu %llu %llu %llu %llu %llu %llu %llu"

#define CPU_ELEMENTS_3 9 // change this if you change the format string
#define CPU_INFO_FORMAT_3 "cpu  %llu %llu %llu %llu %llu %llu %llu %llu %llu"
        static const char procfile[] = "/proc/stat";
        int rc = 0;
        int myerrno = 0;
        int elements = 0;
        const char *cpustr = NULL;
        char statbuff[1024];
        unsigned long long guest = 0;

        if (!p->initd) {
                p->procfd = open(procfile, O_RDONLY, 0);
                if(p->procfd == -1) {
                        switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_CRIT, "Failed to open CPU statistics file %s: %s\n", procfile, strerror(myerrno));
                        return -1;
                }
                p->initd = 1;
        } else {
                lseek(p->procfd, 0L, SEEK_SET);
        }

        rc = read(p->procfd, statbuff, sizeof(statbuff) - 1);
        if (rc <= 0) {
                myerrno = errno;
                switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_CRIT, "Failed to read CPU statistics file %s: %s\n", procfile, strerror(myerrno));
                return -1;
        } else {
          statbuff[rc] = '\0';
        }

        cpustr = strstr(statbuff, "cpu ");
        if (!cpustr) {
                switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_CRIT, "wrong format for Linux proc cpu statistics: missing cpu string\n");
                return -1;
        }

        /* test each of the known formats starting from the bigger one */
        elements = sscanf(cpustr, CPU_INFO_FORMAT_3, user, nice, system, idle, iowait, irq, softirq, steal, &guest);
        if (elements == CPU_ELEMENTS_3) {
                *user += guest; /* guest operating system's run in user space */
                return 0;
        }

        elements = sscanf(cpustr, CPU_INFO_FORMAT_2, user, nice, system, idle, iowait, irq, softirq, steal);
        if (elements == CPU_ELEMENTS_2) {
                return 0;
        }

        elements = sscanf(cpustr, CPU_INFO_FORMAT_1, user, nice, system, idle, iowait, irq, softirq);
        if (elements == CPU_ELEMENTS_1) {
                *steal = 0;
                return 0;
        }

        switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_CRIT, "Unexpected format for Linux proc cpu statistics: %s\n", cpustr);
        return -1;
}

SWITCH_DECLARE(switch_bool_t) switch_get_system_idle_time(switch_profile_timer_t *p, double *idle_percentage)
{
        unsigned long long user, nice, system, idle, iowait, irq, softirq, steal;
        unsigned long long usertime, kerneltime, idletime, totaltime, halftime;
        int x;

        *idle_percentage = 100.0;
        if (p->disabled) {
                return SWITCH_FALSE;
        }

        if (read_cpu_stats(p, &user, &nice, &system, &idle, &iowait, &irq, &softirq, &steal)) {
                switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_CRIT, "Failed to retrieve Linux CPU statistics, disabling profile timer ...\n");
                p->disabled = 1;
                return SWITCH_FALSE;
        }

        if (!p->valid_last_times) {
                // we dont strictly need to save all of them but I feel code is more clear if we do
                p->valid_last_times = 1;
                p->last_user_time = user;
                p->last_nice_time = nice;
                p->last_system_time = system;
                p->last_irq_time = irq;
                p->last_soft_irq_time = softirq;
                p->last_io_wait_time = iowait;
                p->last_steal_time = steal;
                p->last_idle_time = idle;
                p->last_percentage_of_idle_time = 100.0;
                *idle_percentage = p->last_percentage_of_idle_time;
                return SWITCH_TRUE;
        }

        usertime = (user - p->last_user_time) + (nice - p->last_nice_time);
        kerneltime = (system - p->last_system_time) + (irq - p->last_irq_time) + (softirq - p->last_soft_irq_time);
        kerneltime += (iowait - p->last_io_wait_time);
        kerneltime += (steal - p->last_steal_time);
        idletime = (idle - p->last_idle_time);

        totaltime = usertime + kerneltime + idletime;

        if (totaltime <= 0) {
                // this may happen if not enough time has elapsed and the jiffies counters are the same than the last time we checked
                // jiffies depend on timer interrupts which depend on the number of HZ compile time setting of the kernel
                // typical configs set HZ to 100 (that means, 100 jiffies updates per second, that is one each 10ms)
                // avoid an arithmetic exception and return the same values
                *idle_percentage = p->last_percentage_of_idle_time;
                return SWITCH_TRUE;
        }

        halftime = totaltime / 2UL;

        p->last_idle_time_index += 1;
        if ( p->last_idle_time_index >= p->cpu_idle_smoothing_depth ) {
          p->last_idle_time_index = 0;
        }
        p->percentage_of_idle_time_ring[p->last_idle_time_index] = ((100 * idletime + halftime) / totaltime);

        p->last_percentage_of_idle_time = 0;
        for ( x = 0; x < p->cpu_idle_smoothing_depth; x++ ) {
          //switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_CRIT, "IDLE TIME: (%d)[%lf]\n", x, p->percentage_of_idle_time_ring[x]);
          p->last_percentage_of_idle_time += p->percentage_of_idle_time_ring[x];
        }
        p->last_percentage_of_idle_time /= p->cpu_idle_smoothing_depth;

        *idle_percentage = p->last_percentage_of_idle_time;
        //switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_CRIT, "IDLE TIME finalized:   [%lf]\n", *idle_percentage);

        p->last_user_time = user;
        p->last_nice_time = nice;
        p->last_system_time = system;
        p->last_irq_time = irq;
        p->last_soft_irq_time = softirq;
        p->last_io_wait_time = iowait;
        p->last_steal_time = steal;
        p->last_idle_time = idle;

        return SWITCH_TRUE;
}

#elif defined (WIN32) || defined (WIN64)

SWITCH_DECLARE(switch_bool_t) switch_get_system_idle_time(switch_profile_timer_t *p, double *idle_percentage)
{
        FILETIME idleTime;
        FILETIME kernelTime;
        FILETIME userTime;
        __int64 i64UserTime, i64KernelTime, i64IdleTime;
  
        if (!GetSystemTimes(&idleTime, &kernelTime, &userTime)) {
                return SWITCH_FALSE;
        }
  
        i64UserTime = (__int64)userTime.dwLowDateTime | ((__int64)userTime.dwHighDateTime << 32);

        i64KernelTime = (__int64)kernelTime.dwLowDateTime | ((__int64)kernelTime.dwHighDateTime << 32);

        i64IdleTime = (__int64)idleTime.dwLowDateTime | ((__int64)idleTime.dwHighDateTime << 32);

        if (p->valid_last_times) {
                __int64 i64User = i64UserTime - p->i64LastUserTime;
                __int64 i64Kernel = i64KernelTime - p->i64LastKernelTime;
                __int64 i64Idle = i64IdleTime - p->i64LastIdleTime;
                __int64 i64System = i64User + i64Kernel;
                 unsigned int x;

                p->last_idle_time_index += 1;
                if ( p->last_idle_time_index >= p->cpu_idle_smoothing_depth ) {
                  p->last_idle_time_index = 0;
                }
                p->percentage_of_idle_time_ring[p->last_idle_time_index] = 100.0 * i64Idle / i64System;

                *idle_percentage = 0;
                for (x = 0; x < p->cpu_idle_smoothing_depth; x++ ) {
                  *idle_percentage += p->percentage_of_idle_time_ring[x];
                }
                *idle_percentage /= p->cpu_idle_smoothing_depth;
        } else {
                *idle_percentage = 100.0;
                p->valid_last_times = 1;
        }

        /* Remember current value for the next call */
        p->i64LastUserTime = i64UserTime;
        p->i64LastKernelTime = i64KernelTime;
        p->i64LastIdleTime = i64IdleTime;

        /* Success */
        return SWITCH_TRUE;
}

#else

  /* Unsupported */
SWITCH_DECLARE(switch_bool_t) switch_get_system_idle_time(switch_profile_timer_t *p, double *idle_percentage)
{
        *idle_percentage = 100.0;
        return SWITCH_FALSE;
}

#endif

SWITCH_DECLARE(switch_profile_timer_t *)switch_new_profile_timer(void)
{
  unsigned int x;
  switch_profile_timer_t *p = calloc(1, sizeof(switch_profile_timer_t));

  if ( runtime.cpu_idle_smoothing_depth && runtime.cpu_idle_smoothing_depth > 0 ) {
          p->cpu_idle_smoothing_depth = runtime.cpu_idle_smoothing_depth;
  } else {
          p->cpu_idle_smoothing_depth = 30;
  }

  p->percentage_of_idle_time_ring = calloc(1, sizeof(double) * p->cpu_idle_smoothing_depth);

  for ( x = 0; x < p->cpu_idle_smoothing_depth; x++ ) {
          p->percentage_of_idle_time_ring[x] = 100.0;
  }

  return p;
}

SWITCH_DECLARE(void) switch_delete_profile_timer(switch_profile_timer_t **p)
{
        if (!p) return;

#ifdef __linux__
        close((*p)->procfd);
#endif
        free((*p)->percentage_of_idle_time_ring);
        free(*p);
        *p = NULL;
}

/* For Emacs:
 * Local Variables:
 * mode:c
 * indent-tabs-mode:t
 * tab-width:4
 * c-basic-offset:4
 * End:
 * For VIM:
 * vim:set softtabstop=4 shiftwidth=4 tabstop=4 noet:
 */