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 * modification, are permitted provided that the following conditions are
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 *
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 * notice, this list of conditions and the following disclaimer.
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 * in the documentation and/or other materials provided with the
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 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
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 * 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
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#include "test/cpp/qps/usage_timer.h"

#include <grpc/support/time.h>
#include <sys/resource.h>
#include <sys/time.h>

UsageTimer::UsageTimer() : start_(Sample()) {}

double UsageTimer::Now() {
  auto ts = gpr_now(GPR_CLOCK_REALTIME);
  return ts.tv_sec + 1e-9 * ts.tv_nsec;
}

static double time_double(struct timeval* tv) {
  return tv->tv_sec + 1e-6 * tv->tv_usec;
}

UsageTimer::Result UsageTimer::Sample() {
  struct rusage usage;
  struct timeval tv;
  gettimeofday(&tv, NULL);
  getrusage(RUSAGE_SELF, &usage);

  Result r;
  r.wall = time_double(&tv);
  r.user = time_double(&usage.ru_utime);
  r.system = time_double(&usage.ru_stime);
  return r;
}

UsageTimer::Result UsageTimer::Mark() const {
  Result s = Sample();
  Result r;
  r.wall = s.wall - start_.wall;
  r.user = s.user - start_.user;
  r.system = s.system - start_.system;
  return r;
}