Server programming in use...FiaDot

http://www-106.ibm.com/developerworks/linux/library/l-distcc.html?ca=dgr-lnxw01distccTips

class CA
{
public:
CA() { ::InitializeCriticalSection(&m_cs);} ;
virtual ~CA() { ::DeleteCriticalSection(&m_cs);};

protected:
int m_nCnt;
CRITICAL_SECTION m_cs;

};

class CB_A : public CA
{
public:
CB_A() { m_nCnt = 0; };
virtual ~CB_A() {};

void run()
{
m_nCnt++;
};
};

class CB_B : public CA
{
public:
CB_B() { m_nCnt = 0; };
virtual ~CB_B() {};

void run()
{
::EnterCriticalSection(&m_cs);
m_nCnt++;
::LeaveCriticalSection(&m_cs);
};
};

class CA2
{
public:
CA2() {};
virtual ~CA2() {};

protected:
int m_nCnt;
};

class CB2_A : public CA2
{
public:
CB2_A() {m_nCnt = 0; };
virtual ~CB2_A() {};

void run()
{
m_nCnt++;
};

};

class CB2_B_ORI : public CA2
{
public:
CB2_B_ORI() { ::InitializeCriticalSection(&m_cs);};
virtual ~CB2_B_ORI() { ::DeleteCriticalSection(&m_cs);};

protected:
CRITICAL_SECTION m_cs;
};


class CB2_B : public CB2_B_ORI
{
public:
CB2_B() { m_nCnt = 0;};
virtual ~CB2_B() { };

void run()
{
::EnterCriticalSection(&m_cs);
m_nCnt++;
::LeaveCriticalSection(&m_cs);
};

};

DWORD oldTime = timeGetTime();


for(int k=0;k<1;k++)
{
for(int n=0;n<100000;n++)
{

#ifdef _TEST1
CB_A cls1;
CB_B cls2;
#else
CB2_A cls1;
CB2_B cls2;
#endif

cls1.run();
cls2.run();
}

}

DWORD newTime = timeGetTime();

printf(" %d ", newTime - oldTime );


둘의 결과를 비교했을때 타입2가 더 빨랐다.

DWORD oldTime = timeGetTime();

for(int k=0;k<1;k++)
{
#ifdef _TEST1
CB_A cls1;
CB_B cls2;
#else
CB2_A cls1;
CB2_B cls2;
#endif
for(int n=0;n<100000;n++)
{
cls1.run();
cls2.run();
}

}

DWORD newTime = timeGetTime();

printf(" %d ", newTime - oldTime );

근소한 차이를 보였는데 타입1의 성능이 나았다.

One must write good code. One must write perfect code. One must write as efficient code as possible. One thing which amazes me is that there are number of people out there in C++ world who''re still checking for pointer being NULL (0) before deleting it. Here''s the pseudo-code:


void Foo()
{
CBar *pBar = new CBar();

// Do something with pBar (validate, use) ...

if (0 != pBar)
{
delete pBar;
}
}

Please don''t do this, you can omit the if-statement and just delete the pointer. Everything will be fine. Additional lines of code only: a) make life harder for the people who have to review your code; b) decrease your code coverage numbers; c) demonstrate that you don''t know the language basics.

The obvious places for answers are:

- "Freestore management section" of C++ FAQ
- C/C++ Language Reference in MSDN

For C people - yes, the same applies to free() also, no need to check for NULL. Check out also a draft rationale for the C99 standard. One thing to keep in mind though is that this information is Microsoft-centric, please check the documentation for your compiler first.