Slow File I/O with newer compilers (SPARCompiler 5 and gcc 3)

Question

Well it's more like slow File I, as I'm only really testing Input, but anyway, here goes...
I have a simple program that takes a file of about 250mb and simply loops through the file reading it in chunks of 8,192 bytes.
Basically I'm timing the read speed to try and figure out why there is such a large discrepancy between the older SPARCompiler 3.0.1 : C++ 4.0.1 and the newer 5.0 as well as gcc 3.0 in reading a file. I realize that the old compiler doesn't support STL and that SPARCompiler 5's .h headers basically point to the STL headers, so there is a difference there, but the numbers I get are around 35s with SC 3.0.1 : C++ 4.0.1 to about 90s with SC 5.0 and 76s with gcc 3.0. I understand the numbers are going to vary depending on the test input file size and the machine you're running on, but the ratio's should stay relatively similar if you do run your own tests. That slowdown is pretty much unacceptable in my opinion and I really want the benefits of a new compiler, am I doing something wrong, is this a known issue??
Command Lines (I did my best to try with different versions of the OS, but Sun licensing makes it hard!):
With C++ 4.0.1 (tried on Solaris 2.6 and 2.7)
CC -fast -o IOtest.CC io_read_tst.cpp
With C++ 5 (used on Solaris 2.5.1 and 2.8)
CC -O3 -o IOtest.CC5 io_read_tst.cpp
With gcc 3.0 (tried on Solaris 2.5.1, 2.6, 2.7, and 2.8)
gcc -O3 -o IOtest.gcc3 io_read_tst.cpp
I've got the latest patches for the OS and compilers, I've tried compiling on multiple versions of the OS (Solaris 2.5.1, 2.6, 2.7, and 2.8) and always I get similar results, I know I haven't tested every OS possibility, but you have to re-install the OS to test since the compiler is licensed to only one machine, at least for the SUN Compilers anyway! Any help would be greatly, greatly appreciated, code is as follows:
#include <iostream.h>
#include <fstream.h>
#include <time.h>
int main( )
char sBuffer[8192];
time_t startTime, endTime;
ifstream TestFile;
TestFile.open( "/data4/tax101/taxtab" ); // Change this to a large file local to your system (~250mb)
if( TestFile.fail() )
return( EXIT_FAILURE );
time( &startTime );
while( !TestFile.eof() )
TestFile.read( sBuffer, 8192 );
time( &endTime );
cout << endl << "Read Time: " << endTime - startTime << "s\n";
return( EXIT_SUCCESS );
Thanks,
Lance Beddawi
[email protected]

Answer 1

Alright, here is my code reposted:
// Warning.java
// Reads student data from a text file and writes data to another text file.
import java.util.;
import java.io.;
public class Warning
// // Reads student data (name, semester hours, quality points) from a
// text file, computes the GPA, then writes data to another file
// if the student is placed on academic warning.
public static void main (String[] args)
int creditHrs; // number of semester hours earned
double qualityPts; // number of quality points earned
double gpa; // grade point (quality point) average
Scanner scan=null;
PrintWriter outFile=null;
String name, inputName = "students.txt";
String outputName = "warning.txt";
try
// Set up Scanner to input file
scan=new Scanner(new FileInputStream(inputName));
// Set up the output file stream
outFile = new PrintWriter(new FileWriter(outputName));
// Print a header to the output file
outFile.println ();
outFile.println ("Students on Academic Warning");
outFile.println ();
// Process the input file, one token at a time
while (scan.hasNext())
// Get the credit hours and quality points and
// determine if the student is on warning. If so,
// write the student data to the output file.
name=scan.next();
creditHrs=scan.nextInt();
qualityPts=scan.nextDouble();
gpa=qualityPts/creditHrs;
if ((gpa < 1.5 && creditHrs < 30) || (gpa < 1.75 && creditHrs < 60) || (gpa < 2.0 && creditHrs >= 60))
outFile.print(name " ");
outFile.print(creditHrs " ");
outFile.print(qualityPts " ");
outFile.print(gpa);
//Add a catch for each of the specified exceptions, and in each case
//give as specific a message as you can
catch (FileNotFoundException e)
System.out.println("The file " inputName " was not found.");
catch (IOException e)
System.out.println("The I/O operation failed and " outputName + " could not be created.");
catch (InputMismatchException e)
System.out.println("The input information was not of the right type.");