Changeset 5778738 for lib

Timestamp:

01/07/10 11:04:13 (12 years ago)

Author:

Shane Alcock <salcock@…>

Branches:

4.0.1-hotfixes, cachetimestamps, develop, dpdk-ndag, etsilive, getfragoff, help, libtrace4, master, ndag_format, pfring, rc-4.0.1, rc-4.0.2, rc-4.0.3, rc-4.0.4, ringdecrementfix, ringperformance, ringtimestampfixes

Children:

4b6e1b2

Parents:

2d69532

Message:

• Fixed major bug where we were sleeping whenever a packet did not match a specified BPF filter when reading from a DAG card, rather than immediately checking if there was another suitable packet available. This was causing libtrace to get massively behind in reading packets from the DAG card so the DAG buffer would overflow and packets would be dropped.
• NOTE: the dag2.4 version of this fix has not been fully tested (or even compiled) because we upgraded the box that used to have the old DAG cards in

Location:

lib

Files:

• format_dag24.c (modified) (3 diffs)
• format_dag25.c (modified) (1 diff)

lib/format_dag24.c

@@ -372 +372 @@
         int data;
 
-        data = dag_available(trace);
-        if (data > 0) {
+        do {
+                data = dag_available(trace);
+
+                if (data <= 0)
+                        break;
+
                 event.size = dag_read_packet(trace,packet);
                 //DATA(trace)->dag.diff -= event.size;
@@ -380 +384 @@
                                 event.type = TRACE_EVENT_PACKET;
                         } else {
-                                event.type = TRACE_EVENT_SLEEP;
-                                event.seconds = 0.000001;
-                                return event;
+                                /* Do not sleep - try to read another packet */
+                                continue;
                         }
                 } else {
@@ -392 +395 @@
 
                 return event;
-        }
+        } while (1);
+
         assert(data == 0);
         event.type = TRACE_EVENT_SLEEP;
         event.seconds = 0.0001;
-        return event;
+        event.size = 0;
+        return event;
 }
 

lib/format_dag25.c

@@ -888 +888 @@
         uint32_t flags = 0;
 
-        /* Need to call dag_available so that the top pointer will get
-         * updated, otherwise we'll never see any data! */
-        numbytes = dag_available(trace);
-
-        /* May as well not bother calling dag_get_record if dag_available
-         * suggests that there's no data */
-        if (numbytes != 0)
-                erfptr = dag_get_record(trace);
-        if (erfptr == NULL) {
-                /* No packet available */
-                event.type = TRACE_EVENT_SLEEP;
-                event.seconds = 0.0001;
-                return event;
-        }
-        //dag_form_packet(erfptr, packet);
-        if (dag_prepare_packet(trace, packet, erfptr, TRACE_RT_DATA_ERF,
-                                flags)) {
-                event.type = TRACE_EVENT_TERMINATE;
-                return event;
-        }
-
-
-        event.size = trace_get_capture_length(packet) + trace_get_framing_length(packet);
-        if (trace->filter) {
-                if (trace_apply_filter(trace->filter, packet)) {
+        do {
+                erfptr = NULL;
+                numbytes = 0;
+        
+                /* Need to call dag_available so that the top pointer will get
+                 * updated, otherwise we'll never see any data! */
+                numbytes = dag_available(trace);
+
+                /* May as well not bother calling dag_get_record if 
+                 * dag_available suggests that there's no data */
+                if (numbytes != 0)
+                        erfptr = dag_get_record(trace);
+                if (erfptr == NULL) {
+                        /* No packet available */
+                        event.type = TRACE_EVENT_SLEEP;
+                        event.seconds = 0.0001;
+                        break;
+                }
+                //dag_form_packet(erfptr, packet);
+                if (dag_prepare_packet(trace, packet, erfptr, 
+                                        TRACE_RT_DATA_ERF, flags)) {
+                        event.type = TRACE_EVENT_TERMINATE;
+                        break;
+                }
+
+
+                event.size = trace_get_capture_length(packet) + 
+                                trace_get_framing_length(packet);
+                if (trace->filter) {
+                        if (trace_apply_filter(trace->filter, packet)) {
+                                event.type = TRACE_EVENT_PACKET;
+                        } else {
+                                /* This packet isn't useful so we want to
+                                 * immediately see if there is another suitable
+                                 * one - we definitely DO NOT want to return
+                                 * a sleep event in this case, like we used to
+                                 * do! */
+                                continue;
+                        }
+                } else {
                         event.type = TRACE_EVENT_PACKET;
-                } else {
-                        event.type = TRACE_EVENT_SLEEP;
-                        event.seconds = 0.000001;
-                        return event;
                 }
-        } else {
-                event.type = TRACE_EVENT_PACKET;
-        }
-
-        if (trace->snaplen > 0) {
-                trace_set_capture_length(packet, trace->snaplen);
-        }
+
+                if (trace->snaplen > 0) {
+                        trace_set_capture_length(packet, trace->snaplen);
+                }
+                break;
+        } while (1);
 
         return event;