From 94eedcaf5b47e641e7a15d841f1576ebece2051a Mon Sep 17 00:00:00 2001
From: Ravin Perera <33562092+ravinsp@users.noreply.github.com>
Date: Fri, 5 Feb 2021 17:48:21 +0530
Subject: [PATCH] Added roundtime offset based on contract id. (#238)

---
 src/consensus.cpp | 7 ++++++-
 src/consensus.hpp | 1 +
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/consensus.cpp b/src/consensus.cpp
index 2bb4ca5d..b1c2d707 100644
--- a/src/consensus.cpp
+++ b/src/consensus.cpp
@@ -34,6 +34,11 @@ namespace consensus
         ctx.stage_time = conf::cfg.contract.roundtime / 4;
         ctx.stage_reset_wait_threshold = conf::cfg.contract.roundtime / 10;
 
+        // We use a time window boundry offset based on contract id to vary the window boundries between
+        // different contracts with same round time.
+        std::hash<std::string> str_hasher;
+        ctx.round_boundry_offset = str_hasher(conf::cfg.contract.id) % conf::cfg.contract.roundtime;
+
         // Starting consensus processing thread.
         ctx.consensus_thread = std::thread(run_consensus);
 
@@ -306,7 +311,7 @@ namespace consensus
         if (ctx.stage == 0)
         {
             // This gets the start time of current round window. Stage 0 must start in the window after that.
-            const uint64_t previous_round_start = (((uint64_t)(now / conf::cfg.contract.roundtime)) * conf::cfg.contract.roundtime);
+            const uint64_t previous_round_start = (((uint64_t)((now - ctx.round_boundry_offset) / conf::cfg.contract.roundtime)) * conf::cfg.contract.roundtime) + ctx.round_boundry_offset;
 
             // Stage 0 must start in the next round window.
             // (This makes sure stage 3 gets whichever the remaining time in the round after stages 0,1,2)
diff --git a/src/consensus.hpp b/src/consensus.hpp
index d6e9863f..d1534cd6 100644
--- a/src/consensus.hpp
+++ b/src/consensus.hpp
@@ -71,6 +71,7 @@ namespace consensus
         uint64_t round_start_time = 0;
         uint16_t stage_time = 0;                 // Time allocated to a consensus stage.
         uint16_t stage_reset_wait_threshold = 0; // Minimum stage wait time to reset the stage.
+        uint64_t round_boundry_offset = 0;       // Time window boundry offset based on contract id.
 
         std::optional<sc::execution_context> contract_ctx;
         std::mutex contract_ctx_mutex;