+void
+bwlimit(int amount)
+{
+ static struct timeval bwstart, bwend;
+ static int lamt, thresh = 16384;
+ u_int64_t wait;
+ struct timespec ts, rm;
+
+ if (!timerisset(&bwstart)) {
+ gettimeofday(&bwstart, NULL);
+ return;
+ }
+
+ lamt += amount;
+ if (lamt < thresh)
+ return;
+
+ gettimeofday(&bwend, NULL);
+ timersub(&bwend, &bwstart, &bwend);
+ if (!timerisset(&bwend))
+ return;
+
+ lamt *= 8;
+ wait = (double)1000000L * lamt / limitbw;
+
+ bwstart.tv_sec = wait / 1000000L;
+ bwstart.tv_usec = wait % 1000000L;
+
+ if (timercmp(&bwstart, &bwend, >)) {
+ timersub(&bwstart, &bwend, &bwend);
+
+ /* Adjust the wait time */
+ if (bwend.tv_sec) {
+ thresh /= 2;
+ if (thresh < 2048)
+ thresh = 2048;
+ } else if (bwend.tv_usec < 100) {
+ thresh *= 2;
+ if (thresh > 32768)
+ thresh = 32768;
+ }
+
+ TIMEVAL_TO_TIMESPEC(&bwend, &ts);
+ while (nanosleep(&ts, &rm) == -1) {
+ if (errno != EINTR)
+ break;
+ ts = rm;
+ }
+ }
+
+ lamt = 0;
+ gettimeofday(&bwstart, NULL);
+}
+