On Thursday 24 October 2002 06:11, David S. Miller wrote:

On Wed, 2002-10-23 at 06:42, Roy Sigurd Karlsbakk wrote:

quoted

As far as I've understood, sendfile() won't do much good with large
files. Is this right?

There is always a benefit to using sendfile(), when you use
sendfile() the cpu doesn't touch one byte of the data if
the network card support TX checksumming.  The disk DMAs
to ram, then the net card DMAs from ram.  Simple as that.

Are there any plans of implementing sendfile64() or sendfile() support for 
-D_FILE_OFFSET_BITS=64?

(from man 2 sendfile)
ssize_t sendfile(int out_fd, int in_fd, off_t *offset, size_t count);

int main() {
        ssize_t s1;
        size_t count;
        off_t offset;

        printf("sizeof ssize_t: %d\n", sizeof s1);
        printf("sizeof size_t: %d\n", sizeof count);
        printf("sizeof off_t: %d\n", sizeof offset);
        return 0;
}
$ make
...
$ ./sendfile_test
sizeof ssize_t: 4
sizeof size_t: 4
sizeof off_t: 4
$ 

and - when attempting to build this with -D_FILE_OFFSET_BITS=64 

[roy@roy-sin micro_httpd-O_DIRECT]$ make sendfile_test
gcc -D_DEBUG -Wall -W -D_GNU_SOURCE -D_NO_DIR_ACCESS -D_FILE_OFFSET_BITS=64 
-D_LARGEFILE_SOURCE -DUSE_O_DIRECT -DINETD -Wno-unused -O0 -ggdb -c 
sendfile_test.c
In file included from sendfile_test.c:1:
/usr/include/sys/sendfile.h:26: #error "<sys/sendfile.h> cannot be used with 
_FILE_OFFSET_BITS=64"
make: *** [sendfile_test.o] Error 1

-- 
Roy Sigurd Karlsbakk, Datavaktmester
ProntoTV AS - http://www.pronto.tv/
Tel: +47 9801 3356

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