Merge "Fix PROX generator latency"

2 files changed, 23 insertions, 4 deletions

diff --git a/VNFs/DPPD-PROX/handle_gen.c b/VNFs/DPPD-PROX/handle_gen.c
index fcdbcd62..4bf2e6eb 100644
--- a/VNFs/DPPD-PROX/handle_gen.c
+++ b/VNFs/DPPD-PROX/handle_gen.c
@@ -13,7 +13,6 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 */
-
 #include <rte_mbuf.h>
 #include <pcap.h>
 #include <string.h>
@@ -669,6 +668,20 @@ static int handle_gen_bulk(struct task_base *tbase, struct rte_mbuf **mbufs, uin
 	task_gen_checksum_packets(task, new_pkts, pkt_hdr, send_bulk);
 	ret = task->base.tx_pkt(&task->base, new_pkts, send_bulk, out);
 	task_gen_store_accuracy(task, send_bulk, tsc_before_tx);
+
+	// If we failed to send some packets, we need to do some clean-up:
+
+	if (unlikely(ret)) {
+		// We need re-use the packets indexes not being sent
+		// Hence non-sent packets will not be considered as lost by the receiver when it looks at
+		// packet ids. This should also increase the percentage of packets used for latency measurements
+		task->pkt_queue_index -= ret;
+
+		// In case of failures, the estimate about when we can send next packet (earliest_tsc_next_pkt) is wrong
+		// This would result in under-estimated latency (up to 0 or negative)
+		uint64_t bulk_duration = task_gen_calc_bulk_duration(task, ret);
+		task->earliest_tsc_next_pkt -= bulk_duration;
+	}
 	return ret;
 }
 
@@ -1275,11 +1288,14 @@ static void init_task_gen(struct task_base *tbase, struct task_args *targ)
 		plog_info("\tPort %u: max link speed is %ld Mbps\n",
 			(uint8_t)(task->port - prox_port_cfg), 8 * bytes_per_hz / 1000000);
 	}
+	// There are cases where hz estimate might be slighly over-estimated
+	// This results in too much extrapolation
+	// Only account for 99% of extrapolation to handle cases with up to 1% error clocks
 	for (unsigned int i = 0; i < task->max_frame_size * MAX_PKT_BURST ; i++) {
 		if (bytes_per_hz == UINT64_MAX)
 			task->bytes_to_tsc[i] = 0;
 		else
-			task->bytes_to_tsc[i] = (task->hz * i) / bytes_per_hz;
+			task->bytes_to_tsc[i] = (task->hz * i * 0.99) / bytes_per_hz;
 	}
 
 	if (!strcmp(targ->pcap_file, "")) {
diff --git a/VNFs/DPPD-PROX/handle_lat.c b/VNFs/DPPD-PROX/handle_lat.c
index 93652d47..b4e016ec 100644
--- a/VNFs/DPPD-PROX/handle_lat.c
+++ b/VNFs/DPPD-PROX/handle_lat.c
@@ -437,7 +437,7 @@ static uint32_t task_lat_early_loss_detect(struct task_lat *task, uint32_t packe
 
 static uint64_t tsc_extrapolate_backward(struct task_lat *task, uint64_t tsc_from, uint64_t bytes, uint64_t tsc_minimum)
 {
-#ifdef NO_EXTRAPOLATION
+#ifdef NO_LAT_EXTRAPOLATION
 	uint64_t tsc = tsc_from;
 #else
 	uint64_t tsc = tsc_from - task->bytes_to_tsc[bytes];
@@ -806,11 +806,14 @@ static void init_task_lat(struct task_base *tbase, struct task_args *targ)
 	PROX_PANIC(task->bytes_to_tsc == NULL,
 		"Failed to allocate %u bytes (in huge pages) for bytes_to_tsc\n", max_frame_size);
 
+        // There are cases where hz estimate might be slighly over-estimated
+        // This results in too much extrapolation
+        // Only account for 99% of extrapolation to handle cases with up to 1% error clocks
 	for (unsigned int i = 0; i < max_frame_size * MAX_PKT_BURST ; i++) {
 		if (bytes_per_hz == UINT64_MAX)
 			task->bytes_to_tsc[i] = 0;
 		else
-			task->bytes_to_tsc[i] = (rte_get_tsc_hz() * i) / bytes_per_hz;
+			task->bytes_to_tsc[i] = (rte_get_tsc_hz() * i * 0.99) / bytes_per_hz;
 	}
 }