--- Andrew Morton <[email protected]> wrote:
> Could you send the test app please? (Apologies if you've already done so
> and I missed it).
>
Here it is again... this one skips to just under 4GB before starting.
run with "writetest -m <filename>" for the mmap test.
-Kenny
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// test the write throughput of a sliding mmap window vs simple FILE*
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <string.h>
#include <unistd.h>
#include <time.h>
#include <errno.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/time.h>
int total_bytes = 0;
int last_bytes = 0;
struct timeval last_time;
void timeout(int)
{
struct timeval now;
gettimeofday(&now, 0);
double time_diff = (now.tv_sec - last_time.tv_sec) + ((now.tv_usec - last_time.tv_usec) / 1000000.);
last_time = now;
int new_bytes = total_bytes;
int diff = new_bytes - last_bytes;
printf("wrote %dk %dM bytes in %f seconds -> %fM/sec\n", diff / 1024, diff / (1024 * 1024), time_diff, (diff / (time_diff * 1000000.)));
last_bytes = new_bytes;
}
// tests O_DIRECT + pwrite = fail
// O_DIRECT + truncate = happy
// truncate = happy
// pwrite = happy
// O_DIRECT + truncate = happy
// truncate = happy
// O_DIRECT + pwrite = fail
void do_mapwrite(int fd)
{
// lets write as fast as we can....
int const window_size = 2 * 1024 * 1024; // 2 * 1024 * 1024; // 16k
int const window_pages = window_size / 4096;
int file_page_offset = 0;
long long file_size = window_size;
// fast-forward... by 2046 windows
file_size += 2046u * (2 * 1024 * 1024);
file_page_offset += 2046;
//ftruncate64(fd, file_size);
printf("pwrite to %llx %llu\n", file_size, file_size);
pwrite64(fd, "", 1, file_size);
char* mapping_start = static_cast<char*>(mmap64(0, window_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, file_size - window_size));
// scribble into buffer and walk the window
for (;;) {
memset(mapping_start, 0, window_size);
// grow file
file_size += window_size;
//ftruncate64(fd, file_size);
pwrite64(fd, "", 1, file_size);
file_page_offset += window_pages;
//munmap(mapping_start, window_size);
//mapping_start = static_cast<char*>(mmap64(mapping_start, window_size, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_FIXED, fd, file_size - window_size));
while (remap_file_pages(mapping_start, window_size, 0, file_page_offset, MAP_SHARED /*| MAP_NONBLOCK*/) <0)
perror("remap_file_pages");
total_bytes += window_size;
}
}
void do_filewrite(int fd)
{
FILE* ptr = fdopen(fd, "w+");
int line_len = 80;
char* buf = (char*)malloc(line_len);
memset(buf, 0, line_len);
for (;;) {
fwrite(buf, line_len, 1, ptr);
total_bytes += line_len;
}
}
void do_syswrite(int fd)
{
int line_len = 64 * 1024;
char* buf = (char*)malloc(line_len);
memset(buf, 0, line_len);
for (;;) {
write(fd, buf, line_len);
total_bytes += line_len;
}
}
int main(int argc, char* argv[])
{
if (argc != 3) {
printf("usage: %s -[mfw] <filename>\n", argv[0]);
return 0;
}
if ((argv[1][0] != '-') ||
((argv[1][1] != 'm') &&
(argv[1][1] != 'w') &&
(argv[1][1] != 'f'))) {
printf("usage: %s -[mfw] <filename>\n", argv[0]);
return 0;
}
int fd = open(argv[2], O_RDWR | O_CREAT | O_LARGEFILE | O_DIRECT, 0644);
if (fd < 0) {
perror("open");
return 0;
}
// start the clock...
signal(SIGALRM, timeout);
{
struct itimerval itv;
itv.it_interval.tv_sec = 1;
itv.it_interval.tv_usec = 0;
itv.it_value = itv.it_interval;
setitimer(ITIMER_REAL, &itv, 0);
}
switch (argv[1][1]) {
case 'm': do_mapwrite(fd); break;
case 'f': do_filewrite(fd); break;
case 'w': do_syswrite(fd); break;
}
return 0;
}
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