diff --git a/src/mod/pbkdf2.mod/pbkdf2.c b/src/mod/pbkdf2.mod/pbkdf2.c
index 50a7ee3b3..46e95df34 100644
--- a/src/mod/pbkdf2.mod/pbkdf2.c
+++ b/src/mod/pbkdf2.mod/pbkdf2.c
@@ -73,6 +73,9 @@ static char *pbkdf2_hash(const char *pass, const char *digest_name,
   char *out2;
   unsigned char *buf;
   struct rusage ru1, ru2;
+  double utime, stime;
+  /* log only once as long as rounds are not changed */
+  static int rounds_last, responsiveness;
 
   digest = EVP_get_digestbyname(digest_name);
   if (!digest) {
@@ -114,12 +117,21 @@ static char *pbkdf2_hash(const char *pass, const char *digest_name,
     return NULL;
   }
   if (!ret && !getrusage(RUSAGE_SELF, &ru2)) {
+    utime = (double) (ru2.ru_utime.tv_usec - ru1.ru_utime.tv_usec) / 1000 +
+            (double) (ru2.ru_utime.tv_sec  - ru1.ru_utime.tv_sec ) * 1000;
+    stime = (double) (ru2.ru_stime.tv_usec - ru1.ru_stime.tv_usec) / 1000 +
+            (double) (ru2.ru_stime.tv_sec  - ru1.ru_stime.tv_sec ) * 1000;
     debug4("pbkdf2 method %s rounds %i, user %.3fms sys %.3fms", digest_name,
-           rounds,
-           (double) (ru2.ru_utime.tv_usec - ru1.ru_utime.tv_usec) / 1000 +
-           (double) (ru2.ru_utime.tv_sec  - ru1.ru_utime.tv_sec ) * 1000,
-           (double) (ru2.ru_stime.tv_usec - ru1.ru_stime.tv_usec) / 1000 +
-           (double) (ru2.ru_stime.tv_sec  - ru1.ru_stime.tv_sec ) * 1000);
+           rounds, utime, stime);
+    if (rounds != rounds_last) {
+      rounds_last = rounds;
+      responsiveness = 0;
+    }
+    if (((utime + stime) > 100.0) && !responsiveness) {
+      putlog(LOG_MISC, "*", "PBKDF2 warning: pbkdf2 method %s rounds %i took more than 100ms (user %.3fms sys %.3fms). Consider lowering pbkdf2-rounds for eggdrop's responsiveness.",
+             digest_name, rounds, utime, stime);
+      responsiveness = 1;
+    }
   }
   else {
     debug1("PBKDF2 error: getrusage(): %s", strerror(errno));