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Code

Print a frequency estimate after each burst.

Browse Source 
- tools/cntr/cntr.c (measure, print_f): moved pretty-printing of the
  frequency to a separate function
- tools/cntr/cntr.c (count_bursts): print a frequency estimate after each
  burst
- tools/cntr/cntr.c (count_bursts): added comment explaining when and where
  we take the various samples
This commit is contained in:
Werner Almesberger 2010-11-05 10:14:26 -03:00
parent 43f0bcee36
commit 9361f14875
1 changed files with 57 additions and 18 deletions
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75
cntr/tools/cntr/cntr.c
View File

@ -174,30 +174,77 @@ static void arm_stop(void)
} }
/* ---- output ------------------------------------------------------------- */
static void print_f(double f, int digits)
{
char *f_exp;
if (f > 1000000.0) {
f /= 1000000.0;
f_exp = "M";
} else if (f > 1000.0) {
f /= 1000.0;
f_exp = "k";
} else {
f_exp = "";
}
printf("%1.*f %sHz", digits, f, f_exp);
}
/* ---- burst counter ------------------------------------------------------ */ /* ---- burst counter ------------------------------------------------------ */
/*
* Here is when the various samples are taken:
*
* Activity --------XXXXXXXXXXXXX-------------
* ^ ^ ^^
* | | last||
* start stable now
* |<-t(idle)->|
*
* "start" is the sample before counter activity
* "stable" is the first sample after counter activity
* "last" is the sample immediately preceding "now"
* "now" is the sample currently being processed
*
* The count is printed if t(idle) >= timeout.
*/
static void count_bursts(usb_dev_handle *dev, double timeout) static void count_bursts(usb_dev_handle *dev, double timeout)
{ {
struct sample start, stable, now; struct sample start, stable, now, last;
uint64_t dc, delta_n = 0;
double delta_sum = 0, dt;
arm_stop(); arm_stop();
while (!get_sample(dev, &start)); while (!get_sample(dev, &start));
stable = start; stable = last = start;
while (!stop) { while (!stop) {
while (!get_sample(dev, &now)) while (!get_sample(dev, &now))
if (stop) if (stop)
break; break;
delta_sum += now.t1-last.t1;
delta_n++;
last = now;
if (stable.cntr != now.cntr) { if (stable.cntr != now.cntr) {
stable = now; stable = now;
continue; continue;
} }
if (now.t0-stable.t1 < timeout) if (now.t0-stable.t1 < timeout)
continue; continue;
if (now.cntr == start.cntr) if (now.cntr != start.cntr) {
continue; dc = now.cntr-start.cntr;
printf("%llu\n", (unsigned long long) now.cntr-start.cntr); dt = stable.t1-start.t1-delta_sum/delta_n;
printf("%llu ~ ", (unsigned long long) dc);
if (dt > 0)
print_f(dc/dt, 3);
printf("\n");
fflush(stdout);
}
start = now; start = now;
} }
} }
@ -211,7 +258,7 @@ static void measure(usb_dev_handle *dev, double clock_dev_s, double error_goal)
struct sample start, now; struct sample start, now;
uint64_t dc; uint64_t dc;
double dt, f, error; double dt, f, error;
char *f_exp, *error_exp; char *error_exp;
int i; int i;
arm_stop(); arm_stop();
@ -239,15 +286,6 @@ static void measure(usb_dev_handle *dev, double clock_dev_s, double error_goal)
dc = now.cntr-start.cntr; dc = now.cntr-start.cntr;
dt = (now.t0+now.t1)/2.0-(start.t0+start.t1)/2.0; dt = (now.t0+now.t1)/2.0-(start.t0+start.t1)/2.0;
f = dc/dt; f = dc/dt;
if (f > 1000000.0) {
f /= 1000000.0;
f_exp = "M";
} else if (f > 1000.0) {
f /= 1000.0;
f_exp = "k";
} else {
f_exp = "";
}
if (dc) if (dc)
error = 1.0/dc; /* one count */ error = 1.0/dc; /* one count */
else else
@ -274,8 +312,9 @@ static void measure(usb_dev_handle *dev, double clock_dev_s, double error_goal)
} }
} }
printf("\r%6.1f %1.9f %sHz %3.3f%s ", printf("\r%6.1f ", dt);
dt, f, f_exp, error, error_exp); print_f(f, 9);
printf(" %3.3f%s ", error, error_exp);
fflush(stdout); fflush(stdout);
} }
printf( printf(