/
flushtest.cpp
134 lines (120 loc) · 4.09 KB
/
flushtest.cpp
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#include "stdafx.h"
#include <stdio.h>
#include "../util/goodies.h"
#include <fcntl.h>
namespace mongo {
#if defined(F_FULLFSYNC)
void fullsync(int f) {
fcntl( f, F_FULLFSYNC );
}
#else
void fullsync(int f) {
fdatasync(f);
}
#endif
int main(int argc, char* argv[], char *envp[] ) {
cout << "hello" << endl;
FILE *f = fopen("/data/db/temptest", "a");
if ( f == 0 ) {
cout << "can't open file\n";
return 1;
}
{
Timer t;
for ( int i = 0; i < 50000; i++ )
fwrite("abc", 3, 1, f);
cout << "small writes: " << t.millis() << "ms" << endl;
}
{
Timer t;
for ( int i = 0; i < 10000; i++ ) {
fwrite("abc", 3, 1, f);
fflush(f);
fsync( fileno( f ) );
}
int ms = t.millis();
cout << "flush: " << ms << "ms, " << ms / 10000.0 << "ms/request" << endl;
}
{
Timer t;
for ( int i = 0; i < 500; i++ ) {
fwrite("abc", 3, 1, f);
fflush(f);
fsync( fileno( f ) );
sleepmillis(2);
}
int ms = t.millis() - 500 * 2;
cout << "flush with sleeps: " << ms << "ms, " << ms / 500.0 << "ms/request" << endl;
}
char buf[8192];
for ( int pass = 0; pass < 2; pass++ ) {
cout << "pass " << pass << endl;
{
Timer t;
int n = 500;
for ( int i = 0; i < n; i++ ) {
if ( pass == 0 )
fwrite("abc", 3, 1, f);
else
fwrite(buf, 8192, 1, f);
buf[0]++;
fflush(f);
fullsync(fileno(f));
}
int ms = t.millis();
cout << "fullsync: " << ms << "ms, " << ms / ((double) n) << "ms/request" << endl;
}
{
Timer t;
for ( int i = 0; i < 500; i++ ) {
if ( pass == 0 )
fwrite("abc", 3, 1, f);
else
fwrite(buf, 8192, 1, f);
buf[0]++;
fflush(f);
fullsync(fileno(f));
sleepmillis(2);
}
int ms = t.millis() - 2 * 500;
cout << "fullsync with sleeps: " << ms << "ms, " << ms / 500.0 << "ms/request" << endl;
}
}
// without growing
{
fclose(f);
/* try from beginning of the file, where we aren't appending and changing the file length,
to see if this is faster as the directory entry then doesn't have to be flushed (if noatime in effect).
*/
f = fopen("/data/db/temptest", "r+");
Timer t;
int n = 500;
for ( int i = 0; i < n; i++ ) {
fwrite("xyz", 3, 1, f);
fflush(f);
fullsync(fileno(f));
}
int ms = t.millis();
cout << "fullsync without growing: " << ms << "ms, " << ms / ((double) n) << "ms/request" << endl;
}
// without growing, with delay
{
fclose(f);
/* try from beginning of the file, where we aren't appending and changing the file length,
to see if this is faster as the directory entry then doesn't have to be flushed (if noatime in effect).
*/
f = fopen("/data/db/temptest", "r+");
Timer t;
int n = 500;
for ( int i = 0; i < n; i++ ) {
fwrite("xyz", 3, 1, f);
fflush(f);
fullsync(fileno(f));
sleepmillis(2);
}
int ms = t.millis() - 2 * 500;
cout << "fullsync without growing with sleeps: " << ms << "ms, " << ms / ((double) n) << "ms/request" << endl;
}
return 0;
}
} // namespace mongo