MEDIUM: freq_ctr: reimplement freq_ctr_remain_period() from freq_ctr_total()
Now the function becomes an inline one and only contains a divide and
a max. The divide will automatically go away with constant periods.
diff --git a/include/haproxy/freq_ctr.h b/include/haproxy/freq_ctr.h
index 6016614..3060f2a 100644
--- a/include/haproxy/freq_ctr.h
+++ b/include/haproxy/freq_ctr.h
@@ -148,6 +148,20 @@
*/
unsigned int freq_ctr_remain(struct freq_ctr *ctr, unsigned int freq, unsigned int pend);
+/* Returns the number of remaining events that can occur on this freq counter
+ * while respecting <freq> events per period, and taking into account that
+ * <pend> events are already known to be pending. Returns 0 if limit was reached.
+ */
+static inline uint freq_ctr_remain_period(struct freq_ctr_period *ctr, uint period, uint freq, uint pend)
+{
+ ullong total = freq_ctr_total(ctr, period, pend);
+ uint avg = div64_32(total, period);
+
+ if (avg > freq)
+ avg = freq;
+ return freq - avg;
+}
+
/* return the expected wait time in ms before the next event may occur,
* respecting frequency <freq>, and assuming there may already be some pending
* events. It returns zero if we can proceed immediately, otherwise the wait
@@ -158,8 +172,6 @@
/* process freq counters over configurable periods */
unsigned int read_freq_ctr_period(struct freq_ctr_period *ctr, unsigned int period);
-unsigned int freq_ctr_remain_period(struct freq_ctr_period *ctr, unsigned int period,
- unsigned int freq, unsigned int pend);
/* While the functions above report average event counts per period, we are
* also interested in average values per event. For this we use a different
diff --git a/src/freq_ctr.c b/src/freq_ctr.c
index a2ca040a..d68a784 100644
--- a/src/freq_ctr.c
+++ b/src/freq_ctr.c
@@ -166,56 +166,6 @@
return MAX(wait, 1);
}
-/* Returns the number of remaining events that can occur on this freq counter
- * while respecting <freq> events per period, and taking into account that
- * <pend> events are already known to be pending. Returns 0 if limit was reached.
- */
-unsigned int freq_ctr_remain_period(struct freq_ctr_period *ctr, unsigned int period,
- unsigned int freq, unsigned int pend)
-{
- unsigned int _curr, _past, curr, past;
- unsigned int remain, _curr_tick, curr_tick;
-
- while (1) {
- _curr = ctr->curr_ctr;
- __ha_compiler_barrier();
- _past = ctr->prev_ctr;
- __ha_compiler_barrier();
- _curr_tick = ctr->curr_tick;
- __ha_compiler_barrier();
- if (_curr_tick & 0x1)
- continue;
- curr = ctr->curr_ctr;
- __ha_compiler_barrier();
- past = ctr->prev_ctr;
- __ha_compiler_barrier();
- curr_tick = ctr->curr_tick;
- __ha_compiler_barrier();
- if (_curr == curr && _past == past && _curr_tick == curr_tick)
- break;
- };
-
- remain = curr_tick + period - global_now_ms;
- if (likely((int)remain < 0)) {
- /* We're past the first period, check if we can still report a
- * part of last period or if we're too far away.
- */
- past = curr;
- curr = 0;
- remain += period;
- if ((int)remain < 0)
- past = 0;
- }
- if (likely(past))
- curr += div64_32((unsigned long long)past * remain, period);
-
- curr += pend;
- freq -= curr;
- if ((int)freq < 0)
- freq = 0;
- return freq;
-}
-
/* Returns the total number of events over the current + last period, including
* a number of already pending events <pend>. The average frequency will be
* obtained by dividing the output by <period>. This is essentially made to