From 8b46f631c1f964e535b4b6fd0a7b428241c31a90 Mon Sep 17 00:00:00 2001
From: Andre Puschmann <andre@softwareradiosystems.com>
Date: Sat, 14 Dec 2019 22:34:09 +0100
Subject: [PATCH] add basic TTI stats in stack

---
 srsenb/src/stack/enb_stack_lte.cc |  2 +-
 srsue/hdr/stack/ue_stack_lte.h    |  7 ++++++
 srsue/src/stack/ue_stack_lte.cc   | 42 +++++++++++++++++++++++++++++++
 3 files changed, 50 insertions(+), 1 deletion(-)

diff --git a/srsenb/src/stack/enb_stack_lte.cc b/srsenb/src/stack/enb_stack_lte.cc
index 2d0c816de..7bb03a9d8 100644
--- a/srsenb/src/stack/enb_stack_lte.cc
+++ b/srsenb/src/stack/enb_stack_lte.cc
@@ -77,7 +77,7 @@ int enb_stack_lte::init(const stack_args_t& args_, const rrc_cfg_t& rrc_cfg_)
   rrc_log.init("RRC ", logger);
   gtpu_log.init("GTPU", logger);
   s1ap_log.init("S1AP", logger);
-  stack_log.init("STACK", logger);
+  stack_log.init("STCK", logger);
 
   // Init logs
   mac_log.set_level(args.log.mac_level);
diff --git a/srsue/hdr/stack/ue_stack_lte.h b/srsue/hdr/stack/ue_stack_lte.h
index 773ba25e7..1fb3b1e9c 100644
--- a/srsue/hdr/stack/ue_stack_lte.h
+++ b/srsue/hdr/stack/ue_stack_lte.h
@@ -129,16 +129,23 @@ public:
 private:
   void run_thread() final;
   void run_tti_impl(uint32_t tti);
+  void           calc_tti_stats(const uint32_t duration_us);
+  const uint32_t TTI_STAT_PERIOD           = 1024;
+  const uint32_t TTI_WARN_THRESHOLD_US     = 5000;
+  const uint32_t SYNC_QUEUE_WARN_THRESHOLD = 5;
+  const float    US_PER_MS                 = 1000.0;
   void stop_impl();
 
   bool                running;
   srsue::stack_args_t args;
+  std::vector<uint32_t> proc_time;
 
   // timers
   srslte::timer_handler timers;
 
   // UE stack logging
   srslte::logger*    logger = nullptr;
+  srslte::log_filter log; ///< our own log filter
   srslte::log_filter mac_log;
   srslte::log_filter rlc_log;
   srslte::log_filter pdcp_log;
diff --git a/srsue/src/stack/ue_stack_lte.cc b/srsue/src/stack/ue_stack_lte.cc
index 046b01fb3..175051089 100644
--- a/srsue/src/stack/ue_stack_lte.cc
+++ b/srsue/src/stack/ue_stack_lte.cc
@@ -22,6 +22,9 @@
 #include "srsue/hdr/stack/ue_stack_lte.h"
 #include "srslte/common/logmap.h"
 #include "srslte/srslte.h"
+#include <algorithm>
+#include <chrono>
+#include <numeric>
 
 using namespace srslte;
 
@@ -50,6 +53,8 @@ ue_stack_lte::ue_stack_lte() :
   background_queue_id = pending_tasks.add_queue();
 
   background_tasks.start();
+
+  proc_time.reserve(TTI_STAT_PERIOD);
 }
 
 ue_stack_lte::~ue_stack_lte()
@@ -89,6 +94,10 @@ int ue_stack_lte::init(const stack_args_t& args_, srslte::logger* logger_)
   rrc_log.init("RRC ", logger);
   usim_log.init("USIM", logger);
 
+  // init own logger
+  log.init("STCK", logger);
+  log.set_level(srslte::LOG_LEVEL_INFO);
+
   pool_log.init("POOL", logger);
   pool_log.set_level(srslte::LOG_LEVEL_ERROR);
   byte_buffer_pool::get_instance()->set_log(&pool_log);
@@ -278,10 +287,43 @@ void ue_stack_lte::run_tti(uint32_t tti)
 
 void ue_stack_lte::run_tti_impl(uint32_t tti)
 {
+  auto start = std::chrono::steady_clock::now();
+
+  // perform tasks in this TTI
   mac.run_tti(tti);
   rrc.run_tti(tti);
   nas.run_tti(tti);
   timers.step_all();
+
+  auto end = std::chrono::steady_clock::now();
+  calc_tti_stats(std::chrono::duration_cast<std::chrono::microseconds>(end - start).count());
+}
+
+void ue_stack_lte::calc_tti_stats(const uint32_t duration_us)
+{
+  log.debug("proc_time=%.2fms\n", duration_us / US_PER_MS);
+  if (duration_us > TTI_WARN_THRESHOLD_US) {
+    log.warning("Long TTI proc_time=%.2fms\n", duration_us / US_PER_MS);
+  }
+
+  proc_time.push_back(duration_us);
+  if (proc_time.size() == TTI_STAT_PERIOD) {
+    uint32_t min = 0, max = 0, sum = 0;
+    for (auto& item : proc_time) {
+      max = std::max(max, item);
+      min = std::min(min, item);
+      sum += item;
+    }
+    auto avg = sum / proc_time.size();
+    log.info("proc_time=%.2f,%.2f,%.2f (min,avg,max)\n", min / US_PER_MS, avg / US_PER_MS, max / US_PER_MS);
+
+    proc_time.clear();
+  }
+
+  // print warning if PHY pushes new TTI messages faster than we process them
+  if (pending_tasks.size(sync_queue_id) > SYNC_QUEUE_WARN_THRESHOLD) {
+    log.warning("Detected slow task processing (sync_queue_len=%zd).\n", pending_tasks.size(sync_queue_id));
+  }
 }
 
 /********************