config: Remove redundant explicit setting of default clocks

This patch removes the explicit setting of the clock period for
certain instances of CoherentBus, NonCoherentBus and IOCache where the
specified clock is same as the default value of the system clock. As
all the values used are the defaults, there are no performance
changes. There are similar cases where the toL2Bus is set to use the
parent CPU clock which is already the default behaviour.

The main motivation for these simplifications is to ease the
introduction of clock domains.

configs/example/fs.py

@@ -134,8 +134,8 @@ if is_kvm_cpu(TestCPUClass) or is_kvm_cpu(FutureClass):
     test_sys.vm = KvmVM()
 
 if options.caches or options.l2cache:
-    test_sys.iocache = IOCache(clock = '1GHz',
+    # By default the IOCache runs at the system clock
-                               addr_ranges = test_sys.mem_ranges)
+    test_sys.iocache = IOCache(addr_ranges = test_sys.mem_ranges)
     test_sys.iocache.cpu_side = test_sys.iobus.master
     test_sys.iocache.mem_side = test_sys.membus.slave
 else:

src/cpu/BaseCPU.py

@@ -281,10 +281,10 @@ class BaseCPU(MemObject):
 
     def addTwoLevelCacheHierarchy(self, ic, dc, l2c, iwc = None, dwc = None):
         self.addPrivateSplitL1Caches(ic, dc, iwc, dwc)
-        # Override the default bus clock of 1 GHz and uses the CPU
+        # Set a width of 32 bytes (256-bits), which is four times that
-        # clock for the L1-to-L2 bus, and also set a width of 32 bytes
+        # of the default bus. The clock of the CPU is inherited by
-        # (256-bits), which is four times that of the default bus.
+        # default.
-        self.toL2Bus = CoherentBus(clock = Parent.clock, width = 32)
+        self.toL2Bus = CoherentBus(width = 32)
         self.connectCachedPorts(self.toL2Bus)
         self.l2cache = l2c
         self.toL2Bus.master = self.l2cache.cpu_side

src/dev/CopyEngine.py

@@ -53,8 +53,6 @@ class CopyEngine(PciDevice):
     ChanCnt = Param.UInt8(4, "Number of DMA channels that exist on device")
     XferCap = Param.MemorySize('4kB', "Number of bits of transfer size that are supported")
 
-    # Override the default clock
-    clock = '500MHz'
     latBeforeBegin = Param.Latency('20ns', "Latency after a DMA command is seen before it's proccessed")
     latAfterCompletion = Param.Latency('20ns', "Latency after a DMA command is complete before it's reported as such")
 

src/dev/arm/RealView.py

@@ -118,8 +118,6 @@ class CpuLocalTimer(BasicPioDevice):
     gic = Param.BaseGic(Parent.any, "Gic to use for interrupting")
     int_num_timer = Param.UInt32("Interrrupt number used per-cpu to GIC")
     int_num_watchdog = Param.UInt32("Interrupt number for per-cpu watchdog to GIC")
-    # Override the default clock
-    clock = '1GHz'
 
 class PL031(AmbaIntDevice):
     type = 'PL031'

src/mem/ruby/system/RubySystem.py

@@ -36,7 +36,6 @@ class RubySystem(ClockedObject):
     random_seed = Param.Int(1234, "random seed used by the simulation");
     randomization = Param.Bool(False,
         "insert random delays on message enqueue times");
-    clock = '1GHz'
     block_size_bytes = Param.UInt32(64,
         "default cache block size; must be a power of two");
     mem_size = Param.MemorySize("total memory size of the system");

tests/configs/base_config.py

@@ -161,8 +161,8 @@ class BaseFSSystem(BaseSystem):
     def init_system(self, system):
         BaseSystem.init_system(self, system)
 
-        #create the iocache
+        # create the iocache, which by default runs at the system clock
-        system.iocache = IOCache(clock='1GHz', addr_ranges=system.mem_ranges)
+        system.iocache = IOCache(addr_ranges=system.mem_ranges)
         system.iocache.cpu_side = system.iobus.master
         system.iocache.mem_side = system.membus.slave
 

tests/configs/memtest.py

@@ -39,7 +39,7 @@ cpus = [ MemTest(clock = '2GHz') for i in xrange(nb_cores) ]
 system = System(cpu = cpus, funcmem = SimpleMemory(in_addr_map = False),
                 funcbus = NoncoherentBus(),
                 physmem = SimpleMemory(),
-                membus = CoherentBus(clock="1GHz", width=16))
+                membus = CoherentBus(width=16))
 
 # l2cache & bus
 system.toL2Bus = CoherentBus(clock="2GHz", width=16)

tests/configs/tgen-simple-dram.py

@@ -49,7 +49,7 @@ cpu = TrafficGen(config_file = "tests/quick/se/70.tgen/tgen-simple-dram.cfg")
 
 # system simulated
 system = System(cpu = cpu, physmem = DDR3_1600_x64(),
-                membus = NoncoherentBus(clock="1GHz", width = 16))
+                membus = NoncoherentBus(width = 16))
 
 # add a communication monitor
 system.monitor = CommMonitor()

tests/configs/tgen-simple-mem.py

@@ -49,7 +49,7 @@ cpu = TrafficGen(config_file = "tests/quick/se/70.tgen/tgen-simple-mem.cfg")
 
 # system simulated
 system = System(cpu = cpu, physmem = SimpleMemory(),
-                membus = NoncoherentBus(clock="1GHz", width = 16))
+                membus = NoncoherentBus(width = 16))
 
 # add a communication monitor, and also trace all the packets
 system.monitor = CommMonitor(trace_file = "monitor.ptrc.gz")