i#6938 sched migrate: Separate run queue per output

clients/drcachesim/analyzer_multi.cpp

@@ -564,6 +564,9 @@ analyzer_multi_tmpl_t<RecordType, ReaderType>::init_dynamic_schedule()
     sched_ops.blocking_switch_threshold = op_sched_blocking_switch_us.get_value();
     sched_ops.block_time_multiplier = op_sched_block_scale.get_value();
     sched_ops.block_time_max_us = op_sched_block_max_us.get_value();
+    sched_ops.migration_threshold_us = op_sched_migration_threshold_us.get_value();
+    sched_ops.rebalance_period_us = op_sched_rebalance_period_us.get_value();
+    sched_ops.time_units_per_us = op_sched_time_units_per_us.get_value();
     sched_ops.randomize_next_input = op_sched_randomize.get_value();
     sched_ops.honor_direct_switches = !op_sched_disable_direct_switches.get_value();
 #ifdef HAS_ZIP

clients/drcachesim/common/memtrace_stream.h

@@ -98,6 +98,15 @@ class memtrace_stream_t {
          * i.e., the number of input migrations to this core.
          */
         SCHED_STAT_MIGRATIONS,
+        /**
+         * Counts the number of times this output's runqueue became empty and it took
+         * work from another output's runqueue.
+         */
+        SCHED_STAT_RUNQUEUE_STEALS,
+        /**
+         * Counts the number of output runqueue rebalances triggered by this output.
+         */
+        SCHED_STAT_RUNQUEUE_REBALANCES,
         /** Count of statistic types. */
         SCHED_STAT_TYPE_COUNT,
     };

clients/drcachesim/common/options.cpp

@@ -1002,6 +1002,18 @@ droption_t<double> op_sched_time_units_per_us(
     "of the -sched_*_us values as it converts wall-clock time into the simulated "
     "microseconds measured by those options.");
 
+droption_t<uint64_t> op_sched_migration_threshold_us(
+    DROPTION_SCOPE_ALL, "sched_migration_threshold_us", 500,
+    "Time in simulated microseconds before an input can be migrated across cores",
+    "The minimum time in simulated microseconds that must have elapsed since an input "
+    "last ran on a core before it can be migrated to another core.");
+
+droption_t<uint64_t> op_sched_rebalance_period_us(
+    DROPTION_SCOPE_ALL, "sched_rebalance_period_us", 1500000,
+    "Period in microseconds at which core run queues are load-balanced",
+    "The period in simulated microseconds at which per-core run queues are re-balanced "
+    "to redistribute load.");
+
 // Schedule_stats options.
 droption_t<uint64_t>
     op_schedule_stats_print_every(DROPTION_SCOPE_ALL, "schedule_stats_print_every",

clients/drcachesim/common/options.h

@@ -215,6 +215,9 @@ extern dynamorio::droption::droption_t<std::string> op_cpu_schedule_file;
 extern dynamorio::droption::droption_t<std::string> op_sched_switch_file;
 extern dynamorio::droption::droption_t<bool> op_sched_randomize;
 extern dynamorio::droption::droption_t<bool> op_sched_disable_direct_switches;
+extern dynamorio::droption::droption_t<uint64_t> op_sched_migration_threshold_us;
+extern dynamorio::droption::droption_t<uint64_t> op_sched_rebalance_period_us;
+extern dynamorio::droption::droption_t<double> op_sched_time_units_per_us;
 extern dynamorio::droption::droption_t<uint64_t> op_schedule_stats_print_every;
 extern dynamorio::droption::droption_t<std::string> op_syscall_template_file;
 extern dynamorio::droption::droption_t<uint64_t> op_filter_stop_timestamp;

clients/drcachesim/scheduler/flexible_queue.h

@@ -108,6 +108,15 @@ class flexible_queue_t {
         return entries_[rand_gen_() % size()]; // Undefined if empty.
     }
 
+    // Returns an entry from the back -- or at least not from the front; it's not
+    // guaranteed to be the lowest priority, just not the highest.
+    T
+    back()
+    {
+        assert(!empty());
+        return entries_.back();
+    }
+
     bool
     empty() const
     {