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kohlerkohler
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Storage 3 lecture code
1 parent 0e1a9d1 commit b2dcf17

12 files changed

+367
-0
lines changed

‎storage3/.gitignore

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noncommutative
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[rw][0-9]*sector
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[rw][0-9]*byte
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[rw][0-9]*block
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data

‎storage3/GNUmakefile

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PROGRAMS = noncommutative $(sort $(patsubst %.c,%,$(wildcard r[0-9]*.c)))
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all: $(PROGRAMS) data
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include ../common/rules.mk
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%.o: %.c $(BUILDSTAMP)
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$(CC) $(CPPFLAGS) $(CFLAGS) $(DEPCFLAGS) $(O) -o $@ -c $<
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noncommutative: noncommutative.o
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$(CC) $(CFLAGS) $(O) -o $@ $^ -lm
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r%: r%.o
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$(CC) $(CFLAGS) $(O) -o $@ $^
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data:
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yes 77777777777777777777777777777777777777777 | tr -d '\n' | head -c 51200000 > data
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clean:
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rm -f *.o $(PROGRAMS) data
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rm -rf $(DEPSDIR) *.dSYM
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.PHONY: all clean

‎storage3/iobench.h

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#ifndef IOBENCH_H
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#define IOBENCH_H
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#define _GNU_SOURCE 1
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#include <unistd.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <assert.h>
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#include <string.h>
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#include <limits.h>
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#include <sys/time.h>
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static inline double tstamp(void) {
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struct timeval tv;
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gettimeofday(&tv, 0);
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return tv.tv_sec + tv.tv_usec / 1000000.;
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}
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// Print a report to stderr of # bytes printed, elapsed time, and rate.
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static inline void report(size_t n, double elapsed) {
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fprintf(stderr, "\r%zd bytes %.3f sec %g byte/sec ",
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n, elapsed, n / elapsed);
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}
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// Return the size of a file.
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static inline ssize_t filesize(int fd) {
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struct stat s;
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int r = fstat(fd, &s);
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if (r >= 0 && S_ISREG(s.st_mode) && s.st_size <= SSIZE_MAX)
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return s.st_size;
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else
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return -1;
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}
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#ifndef PRINT_FREQUENCY
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#define PRINT_FREQUENCY 4096
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#endif
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#endif

‎storage3/noncommutative.c

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#include <stdio.h>
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int main() {
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double answer = 0;
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answer += 100000000000;
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for (int i = 0; i < 100000; ++i)
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answer += 0.01;
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printf("%.12g (%a)\n", answer, answer);
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}

‎storage3/r01-directsector.c

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#include "iobench.h"
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int main() {
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#ifndef O_DIRECT
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fprintf(stderr, "ERROR: O_DIRECT not supported here\n");
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# define O_DIRECT 0
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#endif
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#ifndef O_DSYNC
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# define O_DSYNC 0
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#endif
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int fd = STDIN_FILENO;
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if (isatty(fd))
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fd = open("data", O_RDONLY | O_DIRECT | O_DSYNC);
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if (fd < 0) {
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perror("open");
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exit(1);
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}
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size_t size = filesize(fd);
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size_t block_size = 512;
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char* buf;
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posix_memalign((void **) &buf, 512, block_size);
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double start = tstamp();
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size_t n = 0;
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while (n < size) {
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ssize_t r = read(fd, buf, block_size);
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if (r == -1) {
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perror("read");
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exit(1);
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} else if (r != (ssize_t) block_size)
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break;
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n += r;
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if (n % PRINT_FREQUENCY == 0)
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report(n, tstamp() - start);
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}
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close(fd);
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report(n, tstamp() - start);
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fprintf(stderr, "\n");
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}

‎storage3/r02-sector.c

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#include "iobench.h"
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int main() {
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int fd = STDIN_FILENO;
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if (isatty(fd))
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fd = open("data", O_RDONLY);
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if (fd < 0) {
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perror("open");
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exit(1);
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}
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size_t size = filesize(fd);
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char* buf = (char*) malloc(512);
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double start = tstamp();
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size_t n = 0;
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while (n < size) {
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ssize_t r = read(fd, buf, 512);
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if (r == -1) {
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perror("read");
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exit(1);
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} else if (r != 512)
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break;
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n += r;
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if (n % PRINT_FREQUENCY == 0)
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report(n, tstamp() - start);
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}
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close(fd);
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report(n, tstamp() - start);
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fprintf(stderr, "\n");
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}

‎storage3/r03-byte.c

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#include "iobench.h"
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int main() {
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int fd = STDIN_FILENO;
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if (isatty(fd))
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fd = open("data", O_RDONLY);
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if (fd < 0) {
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perror("open");
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exit(1);
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}
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size_t size = filesize(fd);
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char* buf = (char*) malloc(1);
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double start = tstamp();
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size_t n = 0;
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while (n < size) {
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ssize_t r = read(fd, buf, 1);
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if (r == -1) {
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perror("read");
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exit(1);
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} else if (r != 1)
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break;
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n += r;
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if (n % PRINT_FREQUENCY == 0)
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report(n, tstamp() - start);
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}
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close(fd);
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report(n, tstamp() - start);
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fprintf(stderr, "\n");
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}

‎storage3/r04-stdiobyte.c

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#include "iobench.h"
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int main() {
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FILE* f = stdin;
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if (isatty(fileno(f)))
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f = fopen("data", "r");
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if (!f) {
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perror("fopen");
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exit(1);
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}
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size_t size = filesize(fileno(f));
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double start = tstamp();
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size_t n = 0;
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while (n < size) {
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int ch = fgetc(f);
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if (ch == EOF && ferror(f)) {
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perror("fgetc");
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exit(1);
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} else if (ch == EOF)
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break;
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n += 1;
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if (n % PRINT_FREQUENCY == 0)
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report(n, tstamp() - start);
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}
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fclose(f);
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report(n, tstamp() - start);
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fprintf(stderr, "\n");
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}

‎storage3/r05-revbyte.c

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#include "iobench.h"
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int main() {
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int fd = STDIN_FILENO;
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if (isatty(fd))
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fd = open("data", O_RDONLY);
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if (fd < 0) {
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perror("open");
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exit(1);
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}
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size_t size = filesize(fd);
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char* buf = (char*) malloc(1);
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double start = tstamp();
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off_t pos = size;
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size_t n = 0;
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while (pos > 0) {
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pos -= 1;
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if (lseek(fd, pos, SEEK_SET) == (off_t) -1) {
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perror("lseek");
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exit(1);
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}
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ssize_t r = read(fd, buf, 1);
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if (r == -1) {
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perror("read");
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exit(1);
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} else if (r != 1)
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break;
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n += r;
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if (n % PRINT_FREQUENCY == 0)
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report(n, tstamp() - start);
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}
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close(fd);
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report(n, tstamp() - start);
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fprintf(stderr, "\n");
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}

‎storage3/r06-stdiorevbyte.c

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#include "iobench.h"
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int main() {
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FILE* f = stdin;
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if (isatty(fileno(f)))
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f = fopen("data", "r");
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if (!f) {
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perror("fopen");
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exit(1);
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}
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size_t size = filesize(fileno(f));
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double start = tstamp();
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off_t pos = size;
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size_t n = 0;
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while (pos > 0) {
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pos -= 1;
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if (fseek(f, pos, SEEK_SET) == -1) {
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perror("fseek");
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exit(1);
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}
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int ch = fgetc(f);
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if (ch == EOF && ferror(f)) {
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perror("fgetc");
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exit(1);
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} else if (ch == EOF)
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break;
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n += 1;
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if (n % PRINT_FREQUENCY == 0)
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report(n, tstamp() - start);
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}
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fclose(f);
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report(n, tstamp() - start);
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fprintf(stderr, "\n");
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}

‎storage3/r07-stridebyte.c

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#include "iobench.h"
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int main() {
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int fd = STDIN_FILENO;
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if (isatty(fd))
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fd = open("data", O_RDONLY);
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if (fd < 0) {
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perror("open");
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exit(1);
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}
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size_t size = filesize(fd);
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size_t stride = size / 100;
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char* buf = (char*) malloc(1);
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double start = tstamp();
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size_t n = 0, pos = 0;
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while (n < size) {
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ssize_t r = read(fd, buf, 1);
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if (r == -1) {
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perror("read");
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exit(1);
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} else if (r != 1)
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break;
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n += r;
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if (n % PRINT_FREQUENCY == 0)
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report(n, tstamp() - start);
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pos += stride;
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if (pos >= size)
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pos = (pos - size) + 1;
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lseek(fd, pos, SEEK_SET);
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}
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close(fd);
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report(n, tstamp() - start);
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fprintf(stderr, "\n");
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}

‎storage3/r08-stdiostridebyte.c

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#include "iobench.h"
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int main() {
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FILE* f = stdin;
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if (isatty(fileno(f)))
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f = fopen("data", "r");
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if (!f) {
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perror("fopen");
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exit(1);
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}
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size_t size = filesize(fileno(f));
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size_t stride = size / 100;
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double start = tstamp();
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size_t n = 0, pos = 0;
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while (n < size) {
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int ch = fgetc(f);
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if (ch == EOF && ferror(f)) {
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perror("fgetc");
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exit(1);
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} else if (ch == EOF)
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break;
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n += 1;
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if (n % PRINT_FREQUENCY == 0)
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report(n, tstamp() - start);
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pos += stride;
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if (pos >= size)
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pos = (pos - size) + 1;
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fseek(f, pos, SEEK_SET);
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}
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fclose(f);
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report(n, tstamp() - start);
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fprintf(stderr, "\n");
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}

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