sim: Push the global frequency management code into C++.

That makes it available when python is left out, and makes it available
to c++ code without having to call back into python.

Change-Id: If82e7e8eff526f2b957f84afe046e1d56fed4aa2
Reviewed-on: https://gem5-review.googlesource.com/c/14055
Reviewed-by: Srikant Bharadwaj <srikant.bharadwaj@amd.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>

src/python/m5/ticks.py

@@ -31,26 +31,14 @@ from __future__ import print_function
 import sys
 from m5.util import warn
 
-tps = 1.0e12         # default to 1 THz (1 Tick == 1 ps)
-tps_fixed = False    # once set to true, can't be changed
-
-# fix the global frequency and tell C++ about it
+# fix the global frequency
 def fixGlobalFrequency():
     import _m5.core
-    global tps, tps_fixed
-    if not tps_fixed:
-        tps_fixed = True
-        _m5.core.setClockFrequency(int(tps))
-        print("Global frequency set at %d ticks per second" % int(tps))
+    _m5.core.fixClockFrequency()
 
 def setGlobalFrequency(ticksPerSecond):
     from m5.util import convert
-
-    global tps, tps_fixed
-
-    if tps_fixed:
-        raise AttributeError, \
-              "Global frequency already fixed at %f ticks/s." % tps
+    import _m5.core
 
     if isinstance(ticksPerSecond, (int, long)):
         tps = ticksPerSecond
@@ -61,17 +49,20 @@ def setGlobalFrequency(ticksPerSecond):
     else:
         raise TypeError, \
               "wrong type '%s' for ticksPerSecond" % type(ticksPerSecond)
+    _m5.core.setClockFrequency(tps)
 
 # how big does a rounding error need to be before we warn about it?
 frequency_tolerance = 0.001  # 0.1%
 
 def fromSeconds(value):
+    import _m5.core
+
     if not isinstance(value, float):
         raise TypeError, "can't convert '%s' to type tick" % type(value)
 
     # once someone needs to convert to seconds, the global frequency
     # had better be fixed
-    if not tps_fixed:
+    if not _m5.core.clockFrequencyFixed():
         raise AttributeError, \
               "In order to do conversions, the global frequency must be fixed"
 
@@ -79,7 +70,7 @@ def fromSeconds(value):
         return 0
 
     # convert the value from time to ticks
-    value *= tps
+    value *= _m5.core.getClockFrequency()
 
     int_value = int(round(value))
     err = (value - int_value) / value

src/python/pybind11/core.cc

@@ -245,7 +245,11 @@ pybind_init_core(py::module &m_native)
         .def("seedRandom", [](uint64_t seed) { random_mt.init(seed); })
 
 
+        .def("fixClockFrequency", &fixClockFrequency)
+        .def("clockFrequencyFixed", &clockFrequencyFixed)
+
         .def("setClockFrequency", &setClockFrequency)
+        .def("getClockFrequency", &getClockFrequency)
         .def("curTick", curTick)
         ;