実行時間を測定するには？|Android開発
Androidで実行時間を測定し、ログに出力するサンプル。
Java層
測定方法１
long start = System.currentTimeMillis();
// 処理
long end = System.currentTimeMillis();
Log.i("MyApplication", "performance " + (end - start) + " msec");
測定方法２
より精度が高い測定。
long start = System.nanoTime()
// 処理
long end = System.nanoTime();
Log.i("MyApplication", "performance " + (end - start) + " nsec");
Native(JNI)層
C/C++
#include <sys/time.h>
#include <android/log.h>
static unsigned int getTime()
{
struct timeval now_tv;
if (0 != gettimeofday(&now_tv, NULL)) {
return 0;
}
return (unsigned int)((now_tv.tv_sec * 1000000) + now_tv.tv_usec);
}
unsigned int times[2];
times[0] = getTime();
times[1] = getTime();
__android_log_print(ANDROID_LOG_INFO, "app", "DebugTime(%u usec)\n", times[1] - times[0]);
C++(制度の高い測定)
#include "windows.h"
class PerformanceCounter
{
public:
PerformanceCounter(void);
void preparation(void);
void finish(void);
void start(void);
LONGLONG stop(void);
private:
LONGLONG systemQuadPart_;
LARGE_INTEGER startPerformanceCount_;
LARGE_INTEGER stopPerformanceCount_;
DWORD priorityClass_;
int threadPriority_;
};
#include "PerformanceCounter.h"
PerformanceCounter::PerformanceCounter(void)
{
systemQuadPart_ = 0;
threadPriority_ = 0;
priorityClass_ = 0;
LARGE_INTEGER frequency;
bool ret = QueryPerformanceFrequency(&frequency);
if (ret) {
systemQuadPart_ = frequency.QuadPart;
}
}
void PerformanceCounter::preparation(void)
{
priorityClass_ = GetPriorityClass(GetCurrentProcess());
threadPriority_ = GetThreadPriority(GetCurrentThread());
SetPriorityClass(GetCurrentProcess(), REALTIME_PRIORITY_CLASS);
SetThreadPriority(GetCurrentThread(), THREAD_PRIORITY_HIGHEST);
}
void PerformanceCounter::finish(void)
{
SetThreadPriority(GetCurrentThread(), threadPriority_);
SetPriorityClass(GetCurrentProcess(), priorityClass_);
threadPriority_ = 0;
priorityClass_ = 0;
}
void PerformanceCounter::start(void)
{
QueryPerformanceCounter(&startPerformanceCount_);
}
/* return value is msec. */
LONGLONG PerformanceCounter::stop(void)
{
// 周波数の差分が取得できる。
// msec なので 1000倍.
QueryPerformanceCounter(&stopPerformanceCount_);
return ((stopPerformanceCount_.QuadPart - startPerformanceCount_.QuadPart) * 1000 / systemQuadPart_);
}
使い方は、
preparation()start()stop()finish()
stop()の戻り値が測定結果になります。
systemQuadPart_には１秒間の周波数を設定。
開始時と停止時の周波数差分を１秒間の周波数で割ることで実行時間を算出しています。
