[Ace-users] [ace-users] ACE_RW_Process_Mutex

[kul gupta]

Hello Mathew

Below I m attaching my simple code using ACE_RW_Process_Mutex and its
output.



Description of the problem--

I also tried it using ACE_Process_Mutex by just replacing the
ACE_RW_Process_Mutex in code by ACE_Process_Mutex .With ACE_Process_Mutex
,synchronization is proper and writer and reader are acquiring and releasing
in correct order .(when writer is releasing, then only reader is acquiring
and vice versa. The output for the same is in last of the mail).

BUT when using ACE_RW_Process_Mutex ,the writer and reader are not in sync.

If we see the output for this as mentioned below, writer has acquired the
mutex at

88112592 millisec and released at 88114592 millisec i..e writer is working
for 2 sec and has acquired mutex for 2 sec.

(writer acquired    1    at   88112592

 writer released    1   at   88114592)

Now when we see the Reader, it has acquired the mutex at 88112872 millisec.

(Reader acquired   0     at   88112872

Reader released   0     at   88114872)

This should ideally not happen as mutex is still with the writer and it is
relasing at 88114592 millisec.

 int ACE_TMAIN (int argc, ACE_TCHAR *argv[])


{

int count =0;

float ltime=0;

    ACE_RW_Process_Mutex m_RWMutex(ACE_TEXT("MyMutex"));

    if (agrc == 1)                  // For server which is writing

    {

        while (1)

        {

            if (m_RWMutex.acquire_write() == 0)

            {

                ltime = ::GetTickCount();  //number of millisec since the
system has started

                ACE_OS::printf("Writer acquired...%d  at:
%f\n",count++,ltime);

                ACE_OS::sleep(2);

                ltime = ::GetTickCount();

                ACE_OS::printf("Writer releasing... ...%d  at:
%f\n",count++,ltime);

                m_RWMutex.release();

            }

        }

    }

    else                      //For Client which is reading

    {

        while (1)

        {

            if (m_RWMutex.acquire_read() == 0)

            {

               ltime = ::GetTickCount();

               ACE_OS::printf("Reader acquired... ...%d  at:
%f\n",count++,ltime);

                ACE_OS::sleep(2);

                ltime = ::GetTickCount();

                ACE_OS::printf("Reader releasing...%d  at:
%f\n",count++,ltime);

                m_RWMutex.release();

            }

        }

    }

    return 0;

}

OUTPUT  is like this(WITH ACE_RW_Process_Mutex):



Writer            count      TimeStamp(in millisec)


writer acquired    0    at   88110592

writer released    0    at   88112592

writer acquired    1    at   88112592

writer released    1   at   88114592

writer acquired    2    at   88114592

writer released    2    at   88116592

writer acquired    3    at   88116592

writer released    3    at   88118592



Reader

Reader acquired   0     at   88112872

Reader released   0     at   88114872

Reader acquired   1     at   88114872

Reader released   1     at   88116872

Reader acquired   2     at   88116872

Reader released   2     at   88118872

Reader acquired   3     at   88118872





OUTPUT is like this (WITH ACE_Process_Mutex):



Writer            count      TimeStamp(in millisec)



writer acquired    0    at    88560984

writer released    0    at   88562984

writer acquired    1    at   88562984

writer released    1   at   88564984

writer acquired    2    at   88566984

writer released    2    at   88568984

writer acquired    3    at   88570984

writer released    3    at   88572984



Reader

Reader acquired   0     at   88564984

Reader released   0     at   88566984

Reader acquired   1     at   88568984

Reader released   1     at   88570984

Reader acquired   2     at   88572984

Reader released   2     at   88574984

Reader acquired   3     at   88576984

Reader released   3     at   88578984



Thanks

Kul





On 3/3/08, Matthew Gillen <mgillen at bbn.com> wrote:

kul gupta wrote:
> After having a look into ACE_ROOT/examples/Threads ,I implemented the
> following code using ACE_RW_Process_Mutex. and run in both Windows and
> linux5.0. But in both the cases the synchronization is not happening .

It would help if were more specific about what actually /is/ happening.  Do
you see the output messages in the wrong order?  Do you never see some
output messages?

Matt
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