visual studio .net general: We have noticed a significant decrease in the performance of I/O when an
application is built with 2005 as opposed to 2003.

The application uses a combination of putc, fprintf and vfprint and the
time taken to process the same data has increased as shown below

2003 30.0610
2005 nolock 36.0420
2005 lock 38.6810

We get a smaller incresse when we force no locking to be used.
Has anybody else noticeds this and pinned down the problem.

Hello,

can you provide a sample project which can reproduce the problem with
VS.NET? We will perform further research on the project to see what
happened.

Sincerely,

Luke Zhang

Microsoft Online Community Support
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Luke,

The test program I have is shown below


#include <stdio.h>
#include <time.h>


void main(int argc, char *argv[]) {
int i;
time_t start,endtime;

time(&start);
for (i=1; i<argc;++i) {
FILE *f;
int c;
fprintf(stderr, "argv[%d]=%s\n", i, argv[i]);
if ((f = fopen(argv[i], "r")) == NULL) {
char buff[1000];
//snprintf(buff, 1000, "Cannot open %s. Skipping...\n", argv[i]);
sprintf(buff, "Cannot open %s. Skipping...\n", argv[i]);
perror(buff);
continue;
}
while(EOF != (c=getc(f)))
putc(c, stdout);
fclose(f);
}
time(&endtime);
fprintf(stderr,"Elapsed (secs) = %6.3f\n",difftime(endtime,start));
}

I am building it with the command lines

2003:
cl -GF -D_CRT_SECURE_NO_DEPRECATE /wd 4430 /wd 4996 -F0x1000000 -O2 -Oy-
-Ob2 -Zi -GS- my_cat.c -o my_c

2005:
cl -GF -D_CRT_SECURE_NO_DEPRECATE /wd 4430 /wd 4996 -F0x1000000 -O2 -Oy-
-Ob2 -Zi -GS- my_cat.c -o my_cat.2005.exe

I mam running it with a command line of

my_cat.2003.exe input input input input >output
my_cat.2005.exe input input input input >output

The input file is a text file of around 28Mbytes.

The 2003 takes 26 seconds and the 2005 is taking 61 seconds.

Our actual application uses fprint etc as well but this is the simplest
example I have to show the difference.

Thanks




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