hdparm: simplify timing measurement (it wa the last last user
of setitimer in the tree). static.thousand 16 - -16 read_big_block 81 46 -35 getitimer 41 - -41 setitimer 47 - -47 __GI_setitimer 47 - -47 do_time 480 386 -94 ------------------------------------------------------------------------------ (add/remove: 0/4 grow/shrink: 0/2 up/down: 0/-280) Total: -280 bytes M miscutils/hdparm.c
This commit is contained in:
Denis Vlasenko
parent
0d3c6afc93
commit
c3122bca53
@ -429,10 +429,8 @@ static const char *const secu_str[] = {
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#define SIG 0x00ff /* signature location */
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#define SIG_VAL 0x00a5 /* signature value */
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#define TIMING_MB 64
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#define TIMING_BUF_MB 1
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#define TIMING_BUF_BYTES (TIMING_BUF_MB * 1024 * 1024)
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#define BUFCACHE_FACTOR 2
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#undef DO_FLUSHCACHE /* under construction: force cache flush on -W0 */
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@ -505,6 +503,9 @@ struct globals {
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unsigned long hwif_ctrl;
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unsigned long hwif_irq;
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#endif
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#ifdef DO_FLUSHCACHE
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unsigned char flushcache[4] = { WIN_FLUSHCACHE, 0, 0, 0 };
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#endif
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};
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#define G (*(struct globals*)&bb_common_bufsiz1)
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struct BUG_G_too_big {
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@ -1342,22 +1343,17 @@ static void seek_to_zero(/*int fd*/ void)
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xlseek(fd, (off_t) 0, SEEK_SET);
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}
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static int read_big_block(/*int fd,*/ char *buf)
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static void read_big_block(/*int fd,*/ char *buf)
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{
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int i;
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i = read(fd, buf, TIMING_BUF_BYTES);
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if (i != TIMING_BUF_BYTES) {
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bb_error_msg("read(%d bytes) failed (rc=%d)", TIMING_BUF_BYTES, i);
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return 1;
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}
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xread(fd, buf, TIMING_BUF_BYTES);
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/* access all sectors of buf to ensure the read fully completed */
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for (i = 0; i < TIMING_BUF_BYTES; i += 512)
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buf[i] &= 1;
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return 0;
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}
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static unsigned long long do_blkgetsize(/*int fd*/ void)
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static unsigned long long dev_size_mb(/*int fd*/ void)
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{
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union {
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unsigned long long blksize64;
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@ -1365,85 +1361,88 @@ static unsigned long long do_blkgetsize(/*int fd*/ void)
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} u;
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if (0 == ioctl(fd, BLKGETSIZE64, &u.blksize64)) { // returns bytes
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return u.blksize64 / 512;
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return u.blksize64 / (1024 * 1024);
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}
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xioctl(fd, BLKGETSIZE, &u.blksize32); // returns sectors
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return u.blksize32;
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return u.blksize32 / (2 * 1024);
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}
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static void print_timing(unsigned t, double e)
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static void print_timing(unsigned long m, unsigned elapsed_us)
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{
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if (t >= e) /* more than 1MB/s */
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printf("%4d MB in %.2f seconds = %.2f %cB/sec\n", t, e, t / e, 'M');
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else
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printf("%4d MB in %.2f seconds = %.2f %cB/sec\n", t, e, t / e * 1024, 'k');
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unsigned sec = elapsed_us / 1000000;
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unsigned hs = (elapsed_us % 1000000) / 10000;
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printf("%5lu MB in %u.%02u seconds = %lu kB/s\n",
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m, sec, hs,
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/* Trying to not overflow 32-bit arith in m * CONST
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* by keeping CONST not so big. + 1 prevents div-by-0. */
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(m * (1024 * 1000000 / (64*1024))) / (elapsed_us / (64*1024) + 1)
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// ~= (m * 1024 * 1000000) / elapsed_ms
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// = (m * 1024) / (elapsed_ms / 1000000)
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// = kb / elapsed_sec
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);
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}
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static void do_time(int flag /*,int fd*/)
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/* flag = 0 time_cache, 1 time_device */
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static void do_time(int cache /*,int fd*/)
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/* cache=1: time cache: repeatedly read N MB at offset 0
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* cache=0: time device: linear read, starting at offset 0
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*/
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{
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static const struct itimerval thousand = {{1000, 0}, {1000, 0}};
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struct itimerval itv;
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unsigned max_iterations, iterations;
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unsigned start; /* don't need to be long long */
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unsigned elapsed, elapsed2;
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unsigned max_iterations, total_MB, iterations;
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unsigned long total_MB;
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char *buf = xmalloc(TIMING_BUF_BYTES);
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if (mlock(buf, TIMING_BUF_BYTES)) {
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bb_perror_msg("mlock");
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goto quit2;
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}
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if (mlock(buf, TIMING_BUF_BYTES))
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bb_perror_msg_and_die("mlock");
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max_iterations = do_blkgetsize() / (2 * 1024) / TIMING_BUF_MB;
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/* Don't want to read past the end! */
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max_iterations = UINT_MAX;
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if (!cache)
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max_iterations = dev_size_mb() / TIMING_BUF_MB;
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/* Clear out the device request queues & give them time to complete */
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/* Clear out the device request queues & give them time to complete.
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* NB: *small* delay. User is expected to have a clue and to not run
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* heavy io in parallel with measurements. */
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sync();
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sleep(2);
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if (flag == 0) { /* Time cache */
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sleep(1);
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if (cache) { /* Time cache */
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seek_to_zero();
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if (read_big_block(buf))
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goto quit;
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printf(" Timing buffer-cache reads: ");
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read_big_block(buf);
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printf("Timing buffer-cache reads: ");
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} else { /* Time device */
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printf(" Timing buffered disk reads: ");
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printf("Timing buffered disk reads:");
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}
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fflush(stdout);
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iterations = 0;
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/*
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* getitimer() is used rather than gettimeofday() because
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* it is much more consistent (on my machine, at least).
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*/
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//TODO: get rid of
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setitimer(ITIMER_REAL, &thousand, NULL);
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/* Now do the timing */
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iterations = 0;
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start = monotonic_us();
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do {
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if (cache)
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seek_to_zero();
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read_big_block(buf);
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elapsed = (unsigned)monotonic_us() - start;
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++iterations;
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if (flag == 0)
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seek_to_zero();
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if (read_big_block(buf))
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goto quit;
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getitimer(ITIMER_REAL, &itv);
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elapsed = (1000 - itv.it_value.tv_sec) * 1000000
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- itv.it_value.tv_usec;
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} while (elapsed < 3000000 && iterations < max_iterations);
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total_MB = iterations * TIMING_BUF_MB;
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if (flag == 0) {
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/* Now remove the lseek() and getitimer() overheads from the elapsed time */
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setitimer(ITIMER_REAL, &thousand, NULL);
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total_MB = (unsigned long)iterations * TIMING_BUF_MB;
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//printf(" elapsed:%u iterations:%u ", elapsed, iterations);
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if (cache) {
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/* Now remove the lseek() and monotonic_us() overheads
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* from elapsed */
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start = monotonic_us();
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do {
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seek_to_zero();
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getitimer(ITIMER_REAL, &itv);
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elapsed2 = (1000 - itv.it_value.tv_sec) * 1000000
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- itv.it_value.tv_usec;
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elapsed2 = (unsigned)monotonic_us() - start;
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} while (--iterations);
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//printf(" elapsed2:%u ", elapsed2);
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elapsed -= elapsed2;
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total_MB *= BUFCACHE_FACTOR;
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total_MB *= 2; // BUFCACHE_FACTOR (why?)
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flush_buffer_cache();
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}
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print_timing(total_MB, elapsed / 1000000.0);
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quit:
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print_timing(total_MB, elapsed);
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munlock(buf, TIMING_BUF_BYTES);
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quit2:
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free(buf);
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}
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@ -1688,7 +1687,6 @@ static void process_dev(char *devname)
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#ifndef WIN_FLUSHCACHE
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#define WIN_FLUSHCACHE 0xe7
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#endif
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static unsigned char flushcache[4] = { WIN_FLUSHCACHE, 0, 0, 0 };
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#endif /* DO_FLUSHCACHE */
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args[2] = wcache ? 0x02 : 0x82;
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print_flag_on_off(get_wcache, "drive write-caching", wcache);
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@ -1749,7 +1747,7 @@ static void process_dev(char *devname)
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char buf[512];
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flush_buffer_cache();
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if (-1 == read(fd, buf, sizeof(buf)))
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bb_perror_msg("read(%d bytes) failed (rc=%d)", sizeof(buf), -1);
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bb_perror_msg("read(%d bytes) failed (rc=-1)", sizeof(buf));
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}
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#endif /* HDIO_DRIVE_CMD */
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@ -1912,9 +1910,9 @@ static void process_dev(char *devname)
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ioctl_or_warn(fd, BLKRRPART, NULL);
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if (do_ctimings)
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do_time(0 /*,fd*/); /* time cache */
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do_time(1 /*,fd*/); /* time cache */
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if (do_timings)
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do_time(1 /*,fd*/); /* time device */
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do_time(0 /*,fd*/); /* time device */
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if (do_flush)
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flush_buffer_cache();
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close(fd);
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