From e2e4118364b679f5bd7f6eae56c40ee6d039f5eb Mon Sep 17 00:00:00 2001
From: Arnaud Giersch <arnaud.giersch@iut-bm.univ-fcomte.fr>
Date: Thu, 10 Feb 2011 22:12:13 +0100
Subject: [PATCH] Improve timing between iterations.

---
 process.cpp | 30 +++++++++++++++++++++---------
 1 file changed, 21 insertions(+), 9 deletions(-)

diff --git a/process.cpp b/process.cpp
index fe08b33..eeb5d8c 100644
--- a/process.cpp
+++ b/process.cpp
@@ -18,6 +18,18 @@ double process::total_load_init = 0.0;
 double process::total_load_running = 0.0;
 double process::total_load_exit = 0.0;
 
+namespace {
+
+    void sleep_until_date(double& date, double duration = 0.0)
+    {
+        double sleep_duration = date - MSG_get_clock();
+        if (sleep_duration > 0.0)
+            MSG_process_sleep(sleep_duration);
+        date = MSG_get_clock() + duration;
+    }
+
+}
+
 process::process(int argc, char* argv[])
 {
     if (argc < 2 || !(std::istringstream(argv[1]) >> real_load))
@@ -99,6 +111,7 @@ void process::load_balance_loop()
     using std::tr1::bind;
     using std::tr1::placeholders::_1;
 
+    double next_iter_after_date = MSG_get_clock() + opt::min_lb_iter_duration;
     while (still_running()) {
         ++lb_iter;
 
@@ -120,9 +133,8 @@ void process::load_balance_loop()
         std::for_each(neigh.begin(), neigh.end(),
                       bind(&process::ctrl_send, this, _1));
 
-        // block on receiving unless there is something to compute or
-        // to send
-        ctrl_receive(opt::min_lb_iter_duration);
+        sleep_until_date(next_iter_after_date, opt::min_lb_iter_duration);
+        ctrl_receive(0.0);
 
         comm.ctrl_flush(false);
     }
@@ -145,13 +157,13 @@ void process::compute_loop()
     using std::tr1::bind;
     using std::tr1::placeholders::_1;
 
-    double next_iter_after_date = 0.0;
+    double next_iter_after_date = MSG_get_clock() + opt::min_comp_iter_duration;
     while (still_running()) {
         // receive
-        double sleep_duration = real_load
-            ? std::max(MSG_get_clock() - next_iter_after_date, 0.0)
-            : opt::min_comp_iter_duration;
-        data_receive(sleep_duration);
+        if (real_load > 0.0)
+            data_receive(0.0);
+        else
+            data_receive(opt::min_comp_iter_duration);
 
         comm.data_flush(false);
 
@@ -172,7 +184,7 @@ void process::compute_loop()
         comp += flops;
         MSG_task_destroy(task);
 
-        next_iter_after_date = MSG_get_clock() + opt::min_comp_iter_duration;
+        sleep_until_date(next_iter_after_date, opt::min_comp_iter_duration);
     }
 
     XBT_VERB("Going to finalize for %s...", __func__);
-- 
2.39.5