Increase window size for latency accuracy

Accuracy of latency is obtained by writing TX accuracy for packet N
in a later packet i.e. packet N + WINDOW.
If this window is too small, packet N + WINDOW (conveying accuracy
for packet N) might arrive before packet N, resulting in no accuracy
for packet N.
This change increases this window from 64 to 8K packets.
This change should result in a higher number of packets used for
latency measurements when packets are reordered.
This change might have a performance impact as it uses more memory.

Change-Id: I1016fddb66af86605c73a24050238da41cf54152
Signed-off-by: Xavier Simonart <xavier.simonart@intel.com>
Signed-off-by: Patrice Buriez <patrice.buriez@intel.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/VNFs/DPPD-PROX/handle_lat.h b/VNFs/DPPD-PROX/handle_lat.h
index 3cc80461..46f5e7d4 100644
--- a/VNFs/DPPD-PROX/handle_lat.h
+++ b/VNFs/DPPD-PROX/handle_lat.h
@@ -25,6 +25,10 @@
 #include "clock.h"
 
 #define LATENCY_ACCURACY	1
+// If ACCURACY_WINDOW is too small, the accuracy for packet N can be received by lat BEFORE
+// packet N is received (re-ordering) resulting in accuracy being unused
+// 8192 packets is equivalent to 550 micro-seconds at 10Gbps for 64 bytes packets
+#define ACCURACY_WINDOW		8192
 
 struct lat_test {
 	uint64_t tot_all_pkts;