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#include "Profile_Timer.h"
/* Initialize interval timer. */
Profile_Timer::Profile_Timer (void)
{
char buf[20];
::sprintf(buf, "/proc/%d", ::getpid ());
::memset (&this->end_usage_, 0, sizeof this->end_usage_);
::memset (&this->begin_usage_, 0, sizeof this->begin_usage_);
::memset (&this->last_usage_, 0, sizeof this->last_usage_);
if ((this->proc_fd_ = ::open (buf, O_RDONLY, 0)) == -1)
::perror (buf);
}
/* Terminate the interval timer. */
Profile_Timer::~Profile_Timer (void)
{
if (::close (this->proc_fd_) == -1)
::perror ("Profile_Timer::~Profile_Timer");
}
/* Return the resource utilization. */
void
Profile_Timer::get_rusage (prusage_t &rusage)
{
rusage = this->end_usage_;
}
/* Compute the amount of resource utilization since the start time. */
void
Profile_Timer::elapsed_rusage (prusage_t &rusage)
{
rusage.pr_lwpid = this->end_usage_.pr_lwpid - this->last_usage_.pr_lwpid;
rusage.pr_count = this->end_usage_.pr_count - this->last_usage_.pr_count;
rusage.pr_minf = this->end_usage_.pr_minf - this->last_usage_.pr_minf;
rusage.pr_majf = this->end_usage_.pr_majf - this->last_usage_.pr_majf;
rusage.pr_inblk = this->end_usage_.pr_inblk - this->last_usage_.pr_inblk;
rusage.pr_oublk = this->end_usage_.pr_oublk - this->last_usage_.pr_oublk;
rusage.pr_msnd = this->end_usage_.pr_msnd - this->last_usage_.pr_msnd;
rusage.pr_mrcv = this->end_usage_.pr_mrcv - this->last_usage_.pr_mrcv;
rusage.pr_sigs = this->end_usage_.pr_sigs - this->last_usage_.pr_sigs;
this->subtract (rusage.pr_wtime, this->end_usage_.pr_wtime, this->last_usage_.pr_wtime);
this->subtract (rusage.pr_ltime, this->end_usage_.pr_ltime, this->last_usage_.pr_ltime);
this->subtract (rusage.pr_slptime, this->end_usage_.pr_slptime, this->last_usage_.pr_slptime);
rusage.pr_vctx = this->end_usage_.pr_vctx - this->last_usage_.pr_vctx;
rusage.pr_ictx = this->end_usage_.pr_ictx - this->last_usage_.pr_ictx;
rusage.pr_sysc = this->end_usage_.pr_sysc - this->last_usage_.pr_sysc;
rusage.pr_ioch = this->end_usage_.pr_ioch - this->last_usage_.pr_ioch;
}
/* Compute the elapsed time. */
void
Profile_Timer::compute_times (Elapsed_Time &et, prusage_t &end, prusage_t &begin)
{
timespec_t td;
this->subtract (td, end.pr_tstamp, begin.pr_tstamp);
et.real_time = td.tv_sec + ((double) td.tv_nsec) / (1000 * 1000 * 1000);
this->subtract (td, end.pr_utime, begin.pr_utime);
et.user_time = td.tv_sec + ((double) td.tv_nsec) / (1000 * 1000 * 1000);
this->subtract (td, end.pr_stime, begin.pr_stime);
et.system_time = td.tv_sec + ((double) td.tv_nsec) / (1000 * 1000 * 1000);
}
/* Compute the amount of time that has elapsed between start and stop. */
int
Profile_Timer::elapsed_time (Elapsed_Time &et)
{
this->compute_times (et, this->end_usage_, this->begin_usage_);
return 0;
}
/* Determine the difference between T1 and T2. */
void
Profile_Timer::subtract (timespec_t &tdiff, timespec_t &t1, timespec_t &t0)
{
tdiff.tv_sec = t1.tv_sec - t0.tv_sec;
tdiff.tv_nsec = t1.tv_nsec - t0.tv_nsec;
/* Normalize the time. */
while (tdiff.tv_nsec < 0)
{
tdiff.tv_sec--;
tdiff.tv_nsec += (1000 * 1000 * 1000);
}
}
#if defined (DEBUG)
#include <stdlib.h>
extern "C" int gettimeofday (timeval *tp);
const int DEFAULT_ITERATIONS = 1000000;
int
main (int argc, char *argv[])
{
Profile_Timer timer;
int iterations = argc > 1 ? atoi (argv[1]) : DEFAULT_ITERATIONS;
timeval tv;
timer.start ();
for (int i = 0; i < iterations; i++)
gettimeofday (&tv);
timer.stop ();
Profile_Timer::Elapsed_Time et;
timer.elapsed_time (et);
printf ("iterations = %d\n", iterations);
printf ("real time = %f secs, user time = %f secs, system time = %f secs\n",
et.real_time, et.user_time, et.system_time);
printf ("time per call = %f usecs\n", (et.real_time / double (iterations)) * 1000000);
return 0;
}
#endif /* DEBUG */
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