config: Enable elastic trace capture and replay in se/fs

This patch adds changes to the configuration scripts to support elastic
tracing and replay.

The patch adds a command line option to enable elastic tracing in SE mode
and FS mode. When enabled the Elastic Trace cpu probe is attached to O3CPU
and a few O3 CPU parameters are tuned. The Elastic Trace probe writes out
both instruction fetch and data dependency traces. The patch also enables
configuring the TraceCPU to replay traces using the SE and FS script.

The replay run is designed to resume from checkpoint using atomic cpu to
restore state keeping it consistent with FS run flow. It then switches to
TraceCPU to replay the input traces.

5 files changed, 63 insertions, 2 deletions

diff --git a/configs/common/CacheConfig.py b/configs/common/CacheConfig.py
index d54df7490..b96a7011c 100644
--- a/configs/common/CacheConfig.py
+++ b/configs/common/CacheConfig.py
@@ -69,6 +69,13 @@ def config_cache(options, system):
     # Set the cache line size of the system
     system.cache_line_size = options.cacheline_size
 
+    # If elastic trace generation is enabled, make sure the memory system is
+    # minimal so that compute delays do not include memory access latencies.
+    # Configure the compulsory L1 caches for the O3CPU, do not configure
+    # any more caches.
+    if options.l2cache and options.elastic_trace_en:
+        fatal("When elastic trace is enabled, do not configure L2 caches.")
+
     if options.l2cache:
         # Provide a clock for the L2 and the L1-to-L2 bus here as they
         # are not connected using addTwoLevelCacheHierarchy. Use the
diff --git a/configs/common/CpuConfig.py b/configs/common/CpuConfig.py
index 6b530623d..3220acecd 100644
--- a/configs/common/CpuConfig.py
+++ b/configs/common/CpuConfig.py
@@ -53,6 +53,7 @@ _cpu_aliases_all = [
     ("minor", "MinorCPU"),
     ("detailed", "DerivO3CPU"),
     ("kvm", ("ArmKvmCPU", "ArmV8KvmCPU", "X86KvmCPU")),
+    ("trace", "TraceCPU"),
     ]
 
 # Filtered list of aliases. Only aliases for existing CPUs exist in
@@ -108,6 +109,30 @@ def cpu_names():
     """Return a list of valid CPU names."""
     return _cpu_classes.keys() + _cpu_aliases.keys()
 
+def config_etrace(cpu_cls, cpu_list, options):
+    if issubclass(cpu_cls, m5.objects.DerivO3CPU):
+        # Assign the same file name to all cpus for now. This must be
+        # revisited when creating elastic traces for multi processor systems.
+        for cpu in cpu_list:
+            # Attach the elastic trace probe listener. Set the protobuf trace
+            # file names. Set the dependency window size equal to the cpu it
+            # is attached to.
+            cpu.traceListener = m5.objects.ElasticTrace(
+                                instFetchTraceFile = options.inst_trace_file,
+                                dataDepTraceFile = options.data_trace_file,
+                                depWindowSize = 3 * cpu.numROBEntries)
+            # Make the number of entries in the ROB, LQ and SQ very
+            # large so that there are no stalls due to resource
+            # limitation as such stalls will get captured in the trace
+            # as compute delay. For replay, ROB, LQ and SQ sizes are
+            # modelled in the Trace CPU.
+            cpu.numROBEntries = 512;
+            cpu.LQEntries = 128;
+            cpu.SQEntries = 128;
+    else:
+        fatal("%s does not support data dependency tracing. Use a CPU model of"
+              " type or inherited from DerivO3CPU.", cpu_cls)
+
 # The ARM detailed CPU is special in the sense that it doesn't exist
 # in the normal object hierarchy, so we have to add it manually.
 try:
diff --git a/configs/common/MemConfig.py b/configs/common/MemConfig.py
index 286898798..4685cd5d1 100644
--- a/configs/common/MemConfig.py
+++ b/configs/common/MemConfig.py
@@ -187,6 +187,11 @@ def config_mem(options, system):
     cls = get(options.mem_type)
     mem_ctrls = []
 
+    if options.elastic_trace_en and not issubclass(cls, \
+                                                    m5.objects.SimpleMemory):
+        fatal("When elastic trace is enabled, configure mem-type as "
+                "simple-mem.")
+
     # The default behaviour is to interleave memory channels on 128
     # byte granularity, or cache line granularity if larger than 128
     # byte. This value is based on the locality seen across a large
@@ -206,6 +211,11 @@ def config_mem(options, system):
                     options.mem_ranks:
                 mem_ctrl.ranks_per_channel = options.mem_ranks
 
+            if options.elastic_trace_en:
+                mem_ctrl.latency = '1ns'
+                print "For elastic trace, over-riding Simple Memory " \
+                    "latency to 1ns."
+
             mem_ctrls.append(mem_ctrl)
 
     subsystem.mem_ctrls = mem_ctrls
diff --git a/configs/common/Options.py b/configs/common/Options.py
index f4cf9fbd6..45be8e2f8 100644
--- a/configs/common/Options.py
+++ b/configs/common/Options.py
@@ -87,6 +87,19 @@ def addCommonOptions(parser):
                       Only used if multiple programs are specified. If true,
                       then the number of threads per cpu is same as the
                       number of programs.""")
+    parser.add_option("--elastic-trace-en", action="store_true",
+                      help="""Enable capture of data dependency and instruction
+                      fetch traces using elastic trace probe.""")
+    # Trace file paths input to trace probe in a capture simulation and input
+    # to Trace CPU in a replay simulation
+    parser.add_option("--inst-trace-file", action="store", type="string",
+                      help="""Instruction fetch trace file input to
+                      Elastic Trace probe in a capture simulation and
+                      Trace CPU in a replay simulation""", default="")
+    parser.add_option("--data-trace-file", action="store", type="string",
+                      help="""Data dependency trace file input to
+                      Elastic Trace probe in a capture simulation and
+                      Trace CPU in a replay simulation""", default="")
 
     # Memory Options
     parser.add_option("--list-mem-types",
diff --git a/configs/common/Simulation.py b/configs/common/Simulation.py
index 73874674c..13edf601b 100644
--- a/configs/common/Simulation.py
+++ b/configs/common/Simulation.py
@@ -459,10 +459,11 @@ def run(options, root, testsys, cpu_class):
         for i in xrange(np):
             if options.fast_forward:
                 testsys.cpu[i].max_insts_any_thread = int(options.fast_forward)
-            switch_cpus[i].system =  testsys
+            switch_cpus[i].system = testsys
             switch_cpus[i].workload = testsys.cpu[i].workload
             switch_cpus[i].clk_domain = testsys.cpu[i].clk_domain
-            switch_cpus[i].progress_interval = testsys.cpu[i].progress_interval
+            switch_cpus[i].progress_interval = \
+                testsys.cpu[i].progress_interval
             # simulation period
             if options.maxinsts:
                 switch_cpus[i].max_insts_any_thread = options.maxinsts
@@ -470,6 +471,11 @@ def run(options, root, testsys, cpu_class):
             if options.checker:
                 switch_cpus[i].addCheckerCpu()
 
+        # If elastic tracing is enabled attach the elastic trace probe
+        # to the switch CPUs
+        if options.elastic_trace_en:
+            CpuConfig.config_etrace(cpu_class, switch_cpus, options)
+
         testsys.switch_cpus = switch_cpus
         switch_cpu_list = [(testsys.cpu[i], switch_cpus[i]) for i in xrange(np)]