Add support for color-aware meters (#289)

p4lang · Feb 13, 2017 · dd0fa9d · dd0fa9d
1 parent 8a15692
commit dd0fa9d
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Showing 3 changed files with 24 additions and 6 deletions.
diff --git a/include/bm/bm_sim/meters.h b/include/bm/bm_sim/meters.h
@@ -153,7 +153,9 @@ class Meter {
   //!   - `0 <-> GREEN`
   //!   - `1 <-> YELLOW`
   //!   - `2 <-> RED`
-  color_t execute(const Packet &pkt);
+  //! You can optionally provide a pre-color for the meter. If the computed
+  //! color is less than the pre-color, the pre-color will be returned instead.
+  color_t execute(const Packet &pkt, color_t pre_color = 0);
 
   void serialize(std::ostream *out) const;
   void deserialize(std::istream *in);
@@ -220,7 +222,7 @@ class MeterArray : public NamedP4Object {
   //! Executes the meter at index \p idx on the given packet and returns the
   //! correct integral color value.
   //! See Meter::execute() for more information.
-  color_t execute_meter(const Packet &pkt, size_t idx);
+  color_t execute_meter(const Packet &pkt, size_t idx, color_t pre_color = 0);
 
   template<class RAIt>
   MeterErrorCode set_rates(const RAIt first, const RAIt last) {

diff --git a/src/bm_sim/meters.cpp b/src/bm_sim/meters.cpp
@@ -66,7 +66,7 @@ Meter::reset_rates() {
 }
 
 Meter::color_t
-Meter::execute(const Packet &pkt) {
+Meter::execute(const Packet &pkt, color_t pre_color) {
   color_t packet_color = 0;
 
   if (!configured) return packet_color;
@@ -101,7 +101,7 @@ Meter::execute(const Packet &pkt) {
     }
   }
 
-  return packet_color;
+  return std::max(pre_color, packet_color);
 }
 
 void
@@ -155,9 +155,9 @@ MeterArray::MeterArray(const std::string &name, p4object_id_t id,
 }
 
 MeterArray::color_t
-MeterArray::execute_meter(const Packet &pkt, size_t idx) {
+MeterArray::execute_meter(const Packet &pkt, size_t idx, color_t pre_color) {
   BMLOG_DEBUG_PKT(pkt, "Executing meter {}[{}]", get_name(), idx);
-  return meters[idx].execute(pkt);
+  return meters[idx].execute(pkt, pre_color);
 }
 
 MeterArray::MeterErrorCode

diff --git a/tests/test_meters.cpp b/tests/test_meters.cpp
@@ -175,3 +175,19 @@ TEST_F(MetersTest, GetRates) {
     ASSERT_EQ(rates[i].burst_size, retrieved_rates[i].burst_size);
   }
 }
+
+TEST_F(MetersTest, PreColor) {
+  const color_t GREEN = 0;
+  const color_t RED = 1;
+
+  Meter meter(MeterType::PACKETS, 1);
+  // 2 packets per second, burst size of 3
+  Meter::rate_config_t rate = {0.000002, 3};
+  meter.set_rates({rate});
+
+  Packet pkt = get_pkt(128);
+
+  ASSERT_EQ(GREEN, meter.execute(pkt));
+  ASSERT_EQ(RED, meter.execute(pkt, RED));
+  ASSERT_EQ(GREEN, meter.execute(pkt));
+}