cosmopolitan/examples/bigmem.c

103 lines
3.7 KiB
C

#if 0
/*─────────────────────────────────────────────────────────────────╗
│ To the extent possible under law, Justine Tunney has waived │
│ all copyright and related or neighboring rights to this file, │
│ as it is written in the following disclaimers: │
│ • http://unlicense.org/ │
│ • http://creativecommons.org/publicdomain/zero/1.0/ │
╚─────────────────────────────────────────────────────────────────*/
#endif
#include "libc/calls/calls.h"
#include "libc/calls/hefty/copyfile.h"
#include "libc/calls/hefty/spawn.h"
#include "libc/calls/struct/stat.h"
#include "libc/log/check.h"
#include "libc/macros.h"
#include "libc/runtime/gc.h"
#include "libc/runtime/runtime.h"
#include "libc/stdio/stdio.h"
#include "libc/str/str.h"
#include "libc/sysv/consts/auxv.h"
#include "libc/sysv/consts/clock.h"
#include "libc/sysv/consts/fileno.h"
#include "libc/sysv/consts/madv.h"
#include "libc/sysv/consts/map.h"
#include "libc/sysv/consts/o.h"
#include "libc/sysv/consts/prot.h"
#include "libc/time/time.h"
#include "libc/x/x.h"
/**
* @fileoverview Overcommit tutorial.
* You can allocate memory like a central banker prints money.
*/
/* #define kHugeAmount (10LU * 1024LU * 1024LU * 1024LU * 1024LU) */
#define kHugeAmount (1LU * 1024LU * 1024LU * 1024LU)
int copyfile2(const char *frompath, const char *topath, bool dontoverwrite) {
struct stat st;
ssize_t transferred;
int rc, fromfd, tofd;
int64_t inoffset, outoffset;
rc = -1;
if ((fromfd = open(frompath, O_RDONLY | O_DIRECT, 0)) != -1) {
if (fstat(fromfd, &st) != -1 &&
(tofd =
open(topath,
O_WRONLY | O_CREAT | O_DIRECT | (dontoverwrite ? O_EXCL : 0),
st.st_mode & 0777)) != -1) {
inoffset = 0;
outoffset = 0;
while (st.st_size &&
(transferred = copy_file_range(fromfd, &inoffset, tofd, &outoffset,
st.st_size, 0)) != -1) {
st.st_size -= transferred;
}
if (!st.st_size) rc = 0;
rc |= close(tofd);
}
rc |= close(fromfd);
}
return rc;
}
int main(int argc, char *argv[]) {
int fd, pid;
size_t size;
long double t1, t2;
const char *core, *core2, *core3;
volatile unsigned char *mem;
size = ROUNDUP(kHugeAmount, PAGESIZE);
core = gc(xasprintf("%s.%s", getauxval(AT_EXECFN), "core"));
core2 = gc(xasprintf("%s.%s", getauxval(AT_EXECFN), "core2"));
core3 = gc(xasprintf("%s.%s", getauxval(AT_EXECFN), "core3"));
CHECK_NE(-1, (fd = open(core, O_RDWR | O_CREAT | O_TRUNC | O_CLOEXEC, 0600)));
CHECK_NE(-1, ftruncate(fd, size));
CHECK_NE(MAP_FAILED,
(mem = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0)));
strcpy(&mem[0], "hello\n\n\n\n\n\n\n\n\n\n");
strcpy(&mem[kHugeAmount / 2], "hello\n\n\n\n\n\n\n\n\n\n");
CHECK_NE(-1, munmap(mem, size));
CHECK_NE(-1,
(pid = spawnve(
0, (int[3]){STDIN_FILENO, STDOUT_FILENO, STDERR_FILENO},
"o/examples/stat.com",
(char *const[]){"o/examples/stat.com", core, NULL}, environ)));
CHECK_NE(-1, waitpid(pid, NULL, 0));
CHECK_NE(-1, close(fd));
t1 = dtime(CLOCK_REALTIME);
CHECK_NE(-1, copyfile(core, core2, 0));
t2 = dtime(CLOCK_REALTIME);
printf("%.6Lf\n", t2 - t1);
t1 = dtime(CLOCK_REALTIME);
CHECK_NE(-1, copyfile2(core, core3, false));
t2 = dtime(CLOCK_REALTIME);
printf("%.6Lf\n", t2 - t1);
/* CHECK_NE(-1, unlink(core)); */
return 0;
}