请教一个关于ACE_Mem_Map的使用问题
最近在学习使用ACE_Mem_Map的时候，发现文件写入的效率比较低，居然比fwrite的效率要低，请大家帮忙看看，是否我的用法不对？多谢了！【代码】main.cpp
#include "ace/OS.h"
#include "ace/Task.h"
#include "ace/Mem_Map.h"
class MyTask : public ACE_Task<ACE_MT_SYNCH>
{
public:
void mmap()
{
char fileName;
sprintf(fileName, "c:\\mmap_%d.log", ACE_Thread::self());
const int BUFFLEN = 1*1024;
char buff;
memset(buff, '1', BUFFLEN);
buff = 0;
time_t t1;
ACE_OS::time(&t1);
printf("THR%d:mmap begin...\n", ACE_Thread::self());
ACE_Mem_Map mmap;
mmap.map(fileName,
static_cast<size_t>(100*1024*BUFFLEN),
O_CREAT|O_RDWR,
ACE_DEFAULT_FILE_PERMS,
PROT_RDWR,
ACE_MAP_SHARED);
char* tmp = (char*)mmap.addr();
for(int i=0; i<100*1024; i++)
{
memcpy(tmp, buff, BUFFLEN);
tmp = tmp + BUFFLEN;
}
mmap.sync();
mmap.close();
time_t t2;
ACE_OS::time(&t2);
printf("THR%d:mmap ended, second[%d]!\n", ACE_Thread::self(), t2 - t1);
}
void unmmap()
{
char fileName;
sprintf(fileName, "c:\\unmmap_%d.log", ACE_Thread::self());
const int BUFFLEN = 1*1024;
char buff;
memset(buff, '1', BUFFLEN);
buff = 0;
time_t t1;
ACE_OS::time(&t1);
printf("THR%d:unmmap begin...\n", ACE_Thread::self());
FILE* fp = ACE_OS::fopen(fileName, "a+b");
for(int i=0; i<100*1024; i++)
{
ACE_OS::fwrite(buff, sizeof(char), BUFFLEN, fp);
}
ACE_OS::fclose(fp);
time_t t2;
ACE_OS::time(&t2);
printf("THR%d:unmmap ended, second[%d]!\n", ACE_Thread::self(), t2 - t1);
}
int start(int tpNum, bool is_mmap)
{
this->is_mmap_ = is_mmap;
this->activate(THR_NEW_LWP|THR_JOINABLE|THR_INHERIT_SCHED, tpNum);
return 0;
}
int svc()
{
this->is_mmap_ ? this->mmap() : this->unmmap();
return 0;
}
private:
bool is_mmap_;
};
int main (int argc, char *argv[])
{
bool is_mmap = false;
int tpNum = 1;
for (int i = 1; i<argc; i++)
{
if(memcmp(argv, "-tpNum=", 7) == 0)
{
tpNum = atoi(&argv);
}
else if(memcmp(argv, "-mmap", 5) == 0)
{
is_mmap = true;
}
}
MyTask task;
task.start(tpNum, is_mmap);
task.wait();
return 0;
}
【执行结果】1个并发和10个并发内存映射方式都要慢，并且特别耗CPU
1、内存映射方式
C:\bin>Mem_Map_Test -mmap
THR3052:mmap begin...
THR3052:mmap ended, second!
C:\bin>Mem_Map_Test -mmap -tpNum=10
THR3132:mmap begin...
THR2456:mmap begin...
THR936:mmap begin...
THR3464:mmap begin...
THR3440:mmap begin...
THR3412:mmap begin...
THR3456:mmap begin...
THR3452:mmap begin...
THR3684:mmap begin...
THR3276:mmap begin...
THR3456:mmap ended, second!
THR3452:mmap ended, second!
THR3684:mmap ended, second!
THR3276:mmap ended, second!
THR3132:mmap ended, second!
THR3464:mmap ended, second!
THR936:mmap ended, second!
THR3440:mmap ended, second!
THR3412:mmap ended, second!
THR2456:mmap ended, second!
2、普通方式
C:\bin>Mem_Map_Test
THR3004:unmmap begin...
THR3004:unmmap ended, second!
C:\bin>Mem_Map_Test -tpNum=10
THR2028:unmmap begin...
THR2808:unmmap begin...
THR3224:unmmap begin...
THR3752:unmmap begin...
THR3036:unmmap begin...
THR2304:unmmap begin...
THR1892:unmmap begin...
THR2540:unmmap begin...
THR3736:unmmap begin...
THR2536:unmmap begin...
THR3224:unmmap ended, second!
THR3036:unmmap ended, second!
THR1892:unmmap ended, second!
THR2304:unmmap ended, second!
THR2536:unmmap ended, second!
THR2028:unmmap ended, second!
THR3752:unmmap ended, second!
THR2540:unmmap ended, second!
THR3736:unmmap ended, second!
THR2808:unmmap ended, second! if you only need file IO,read/write are the best!
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