diff --git a/example/osfp_example.c b/example/osfp_example.c
index a9b3017..7924e73 100644
--- a/example/osfp_example.c
+++ b/example/osfp_example.c
@@ -431,7 +431,7 @@ const char *PrintInet(int af, const void *src, char *dst, socklen_t size)
 void example_detect(struct osfp_db *osfp_db, Packet *p)
 {
     int ret;
-    char str_buf[1024] = "";
+    char str_buf[2048] = "";
     //unsigned char *iph = (unsigned char *)(p->iph != NULL ? (void *)p->iph : (void *)p->ip6h);
     struct iphdr *iph;
     struct ip6_hdr *ip6h;
@@ -449,14 +449,19 @@ void example_detect(struct osfp_db *osfp_db, Packet *p)
 
 
     struct osfp_fingerprint fp = {0};
+    if (iph) {
+        osfp_fingerprinting((unsigned char*)iph, (unsigned char*)tcph, tcph_len, &fp, 4);
+    } else if (ip6h) {
+        osfp_fingerprinting((unsigned char*)iph, (unsigned char*)tcph, tcph_len, &fp, 6);
+    } else {
+        goto exit;
+    }
 
     osfp_profile_get_cycle(c1);
     if (iph) {
         result = osfp_ipv4_identify(osfp_db, iph, tcph, tcph_len);
-        osfp_fingerprinting(iph, tcph, tcph_len, &fp, 4);
     } else if (ip6h) {
         result = osfp_ipv6_identify(osfp_db, ip6h, tcph, tcph_len);
-        osfp_fingerprinting(iph, tcph, tcph_len, &fp, 6);
     } else {
         goto exit;
     }
@@ -475,15 +480,20 @@ void example_detect(struct osfp_db *osfp_db, Packet *p)
 
     char *json = osfp_result_score_detail_export(result);
 
-    osfp_fingerprint_to_json_buf(&fp, str_buf, 2048, 0);
-    printf("%s\n", str_buf);
-
-    if (1) {
+    if (debug_enable) {
+        if (p->tcph->ack) {
+            printf("---------------------------  SYN/ACK\n");
+        } else {
+            printf("---------------------------  SYN\n");
+        }
+        osfp_fingerprint_to_json_buf(&fp, str_buf, 2048, 0);
+        printf("%s\n", str_buf);
         printf("Example ipv4 header detect: --------------------------\n");
         printf("Connection info: %s:%d -> %s:%d\n", p->srcip, p->sp, p->dstip, p->dp);
         printf("Most likely os class: %s\n", osfp_result_os_name_get(result));
         printf("Details:\n");
         printf("%s\n", json);
+        fflush(stdout);
     }
 
 exit:
@@ -510,11 +520,6 @@ void process_packet(char *user, struct pcap_pkthdr *h, u_char *pkt)
         goto exit;
     }
 
-    if (p->tcph->ack) {
-        printf("---------------------------  SYN/ACK\n");
-    } else {
-        printf("---------------------------  SYN\n");
-    }
 
     if (p->iph) {
         PrintInet(AF_INET, (const void *)&(p->src.addr_data32[0]), p->srcip, sizeof(p->srcip));
@@ -555,6 +560,8 @@ static void signal_handler(int signum)
         printf("%s: %u\n", osfp_os_class_id_to_name(i), result_os_count[i]);
     }
 
+    fflush(stdout);
+
     exit(0);
 }
 
diff --git a/test/test.c b/test/test.c
index bdce05b..3cb0206 100644
--- a/test/test.c
+++ b/test/test.c
@@ -181,6 +181,8 @@ void test_miss_rate()
     unsigned int other_count = 0;
     unsigned int unknown_count = 0;
     unsigned int identify_failed_count = 0;
+    unsigned int prefiltered_count = 0;
+    unsigned int prefiltered_wrong_count = 0;
     unsigned int wrong_count = 0;
     unsigned int verified_count = 0;
     unsigned int fingerprint_count = 0;
@@ -221,6 +223,12 @@ void test_miss_rate()
 
             const char *fp_str = cJSON_PrintUnformatted(entry);
 
+            struct osfp_fingerprint fp = {0};
+            osfp_fingerprint_from_json(&fp, (char*)fp_str);
+            char str_buf[2048] = "";
+            osfp_fingerprint_to_json_buf(&fp, str_buf, 2048, 0);
+            fprintf(log_file_ptr, "%s\n", str_buf);
+
             struct osfp_result *result = osfp_json_identify(osfp_db, fp_str);
             if (result == NULL) {
                 identify_failed_count++;
@@ -229,12 +237,19 @@ void test_miss_rate()
 
             testresult[result->likely_os_class][os_class]++;
 
+            if (result->details[result->likely_os_class].score == 100) {
+                prefiltered_count++;
+            }
+
             if (os_class == result->likely_os_class) {
                 verified_count++;
                 osfp_result_free(result);
                 continue;
             }
 
+            if (result->details[result->likely_os_class].score == 100) {
+                prefiltered_wrong_count++;
+            }
             wrong_count++;
 
             if (result->likely_os_class == OSFP_OS_CLASS_OTHERS) {
@@ -245,7 +260,7 @@ void test_miss_rate()
                 unknown_count++;
             }
 
-            fprintf(log_file_ptr, "expect: %s, result: %s\n", os_class_json->valuestring, osfp_result_os_name_get(result));
+            fprintf(log_file_ptr, "expect: %s, result: %s, \n", os_class_json->valuestring, osfp_result_os_name_get(result));
 
             char *result_json = osfp_result_score_detail_export(result);
             if (result_json) {
@@ -258,8 +273,8 @@ void test_miss_rate()
         }
     }
 
-    printf("total %u, failed %u, pass %u, wrong %u, other %u, unknown %u\n",
-                fingerprint_count, identify_failed_count, verified_count, wrong_count, other_count, unknown_count);
+    printf("total %u, failed %u, pass %u, prefiltered %u (wrong: %u), wrong %u, other %u, unknown %u\n",
+                fingerprint_count, identify_failed_count, verified_count, prefiltered_count, prefiltered_wrong_count,  wrong_count, other_count, unknown_count);
 
     //printf("miss rate: %d%%\n", 100 - (verified_count * 100 / fingerprint_count));