#define VERSION "v5.4"
-#undef DO_FLUSHCACHE /* under construction: force cache flush on -W0 */
-#define TIMING_BUF_MB 2
+#define TIMING_MB 64
+#define TIMING_BUF_MB 1
#define TIMING_BUF_BYTES (TIMING_BUF_MB * 1024 * 1024)
+#define TIMING_BUF_COUNT (timing_MB / TIMING_BUF_MB)
#define BUFCACHE_FACTOR 2
+#undef DO_FLUSHCACHE /* under construction: force cache flush on -W0 */
+
static int verbose = 0, get_identity = 0, get_geom = 0, noisy = 1, quiet = 0;
static int flagcount = 0, do_flush = 0, is_scsi_hd = 0, is_xt_hd = 0;
static int do_ctimings, do_timings = 0;
return 0;
}
-static void time_cache (int fd)
+static double correction = 0.0;
+
+void time_cache (int fd)
{
+ int i;
char *buf;
struct itimerval e1, e2;
int shmid;
- double elapsed, elapsed2;
- unsigned int iterations, total_MB;
+ int timing_MB = TIMING_MB;
if ((shmid = shmget(IPC_PRIVATE, TIMING_BUF_BYTES, 0600)) == -1) {
bb_perror_msg ("could not allocate sharedmem buf");
sync();
sleep(3);
- /*
+ /* Calculate a correction factor for the basic
+ * overhead of doing a read() from the buffer cache.
+ * To do this, we read the data once to "cache it" and
+ * to force full preallocation of our timing buffer,
+ * and then we re-read it 10 times while timing it.
+ *
* getitimer() is used rather than gettimeofday() because
* it is much more consistent (on my machine, at least).
*/
sync();
sleep(1);
- /* Now do the timing */
- iterations = 0;
+ /* Time re-reading from the buffer-cache */
getitimer(ITIMER_REAL, &e1);
- do {
- ++iterations;
- if (seek_to_zero (fd) || read_big_block (fd, buf))
- goto quit;
- getitimer(ITIMER_REAL, &e2);
- elapsed = (e1.it_value.tv_sec - e2.it_value.tv_sec)
- + ((e1.it_value.tv_usec - e2.it_value.tv_usec) / 1000000.0);
- } while (elapsed < 2.0);
- total_MB = iterations * TIMING_BUF_MB;
-
- elapsed = (e1.it_value.tv_sec - e2.it_value.tv_sec)
+ for (i = (BUFCACHE_FACTOR * TIMING_BUF_COUNT) ; i > 0; --i) {
+ if (seek_to_zero (fd)) goto quit;
+ if (read_big_block (fd, buf)) goto quit;
+ }
+ getitimer(ITIMER_REAL, &e2);
+ correction = (e1.it_value.tv_sec - e2.it_value.tv_sec)
+ ((e1.it_value.tv_usec - e2.it_value.tv_usec) / 1000000.0);
- /* Now remove the lseek() and getitimer() overheads from the elapsed time */
+ /* Now remove the lseek() from the correction factor */
getitimer(ITIMER_REAL, &e1);
- do {
- if (seek_to_zero (fd))
- goto quit;
- getitimer(ITIMER_REAL, &e2);
- elapsed2 = (e1.it_value.tv_sec - e2.it_value.tv_sec)
- + ((e1.it_value.tv_usec - e2.it_value.tv_usec) / 1000000.0);
- } while (--iterations);
-
- elapsed -= elapsed2;
-
- if ((BUFCACHE_FACTOR * total_MB) >= elapsed) /* more than 1MB/s */
- printf("%3u MB in %5.2f seconds = %6.2f MB/sec\n",
- (BUFCACHE_FACTOR * total_MB), elapsed,
- (BUFCACHE_FACTOR * total_MB) / elapsed);
+ for (i = (BUFCACHE_FACTOR * TIMING_BUF_COUNT) ; i > 0; --i) {
+ if (seek_to_zero (fd)) goto quit;
+ }
+ getitimer(ITIMER_REAL, &e2);
+ correction -= (e1.it_value.tv_sec - e2.it_value.tv_sec)
+ + ((e1.it_value.tv_usec - e2.it_value.tv_usec) / 1000000.0);
+
+ if ((BUFCACHE_FACTOR * timing_MB) >= correction) /* more than 1MB/s */
+ printf("%2d MB in %5.2f seconds =%6.2f MB/sec\n",
+ (BUFCACHE_FACTOR * timing_MB), correction,
+ (BUFCACHE_FACTOR * timing_MB) / correction);
else
- printf("%3u MB in %5.2f seconds = %6.2f kB/sec\n",
- (BUFCACHE_FACTOR * total_MB), elapsed,
- (BUFCACHE_FACTOR * total_MB) / elapsed * 1024);
+ printf("%2d MB in %5.2f seconds =%6.2f kB/sec\n",
+ (BUFCACHE_FACTOR * timing_MB), correction,
+ (BUFCACHE_FACTOR * timing_MB) / correction * 1024);
+ correction /= BUFCACHE_FACTOR;
flush_buffer_cache(fd);
sleep(1);
bb_perror_msg ("could not detach sharedmem buf");
}
-static void time_device (int fd)
+void time_device (int fd)
{
+ int i;
char *buf;
double elapsed;
struct itimerval e1, e2;
int shmid;
- unsigned int max_iterations = 1024, total_MB, iterations;
- static long parm;
-
- //
- // get device size
- //
- if (do_ctimings || do_timings) {
- if (ioctl(fd, BLKGETSIZE, &parm))
- bb_perror_msg(" BLKGETSIZE failed");
- else
- max_iterations = parm / (2 * 1024) / TIMING_BUF_MB;
- }
+ int timing_MB = TIMING_MB;
if ((shmid = shmget(IPC_PRIVATE, TIMING_BUF_BYTES, 0600)) == -1) {
bb_perror_msg ("could not allocate sharedmem buf");
setitimer(ITIMER_REAL, &(struct itimerval){{1000,0},{1000,0}}, NULL);
/* Now do the timings for real */
- iterations = 0;
getitimer(ITIMER_REAL, &e1);
- do {
- ++iterations;
- if (read_big_block (fd, buf))
- goto quit;
- getitimer(ITIMER_REAL, &e2);
- elapsed = (e1.it_value.tv_sec - e2.it_value.tv_sec)
- + ((e1.it_value.tv_usec - e2.it_value.tv_usec) / 1000000.0);
- } while (elapsed < 3.0 && iterations < max_iterations);
-
- total_MB = iterations * TIMING_BUF_MB;
- if ((total_MB / elapsed) > 1.0) /* more than 1MB/s */
- printf("%3u MB in %5.2f seconds = %6.2f MB/sec\n",
- total_MB, elapsed, total_MB / elapsed);
+ for (i = TIMING_BUF_COUNT; i > 0; --i) {
+ if (read_big_block (fd, buf)) goto quit;
+ }
+ getitimer(ITIMER_REAL, &e2);
+
+ elapsed = (e1.it_value.tv_sec - e2.it_value.tv_sec)
+ + ((e1.it_value.tv_usec - e2.it_value.tv_usec) / 1000000.0);
+ if (timing_MB >= elapsed) /* more than 1MB/s */
+ printf("%2d MB in %5.2f seconds =%6.2f MB/sec\n",
+ timing_MB, elapsed, timing_MB / elapsed);
else
- printf("%3u MB in %5.2f seconds = %6.2f kB/sec\n",
- total_MB, elapsed, total_MB / elapsed * 1024);
+ printf("%2d MB in %5.2f seconds =%6.2f kB/sec\n",
+ timing_MB, elapsed, timing_MB / elapsed * 1024);
+
+ if (elapsed <= (correction * 2))
+ printf("Hmm.. suspicious results: probably not enough free memory for a proper test.\n");
+#if 0 /* the "estimate" is just plain wrong for many systems.. */
+ else if (correction != 0.0) {
+ printf(" Estimating raw driver speed: ");
+ elapsed -= correction;
+ if (timing_MB >= elapsed) /* more than 1MB/s */
+ printf("%2d MB in %5.2f seconds =%6.2f MB/sec\n",
+ timing_MB, elapsed, timing_MB / elapsed);
+ else
+ printf("%2d MB in %5.2f seconds =%6.2f kB/sec\n",
+ timing_MB, elapsed, timing_MB / elapsed * 1024);
+ }
+#endif
quit:
if (-1 == shmdt(buf))
bb_perror_msg ("could not detach sharedmem buf");
projects / oweals / busybox.git / commitdiff