experiments: add support for specifying gem5 variant

Experiments can explicitly specify opt/fast (default is the latter).

experiments/pyexps/pci_validation.py

@@ -66,6 +66,7 @@ for internal in [True, False]:
 
     for h in [client, server]:
         h.cpu_type = h.cpu_type_cp = 'TimingSimpleCPU'
+        h.variant = 'opt' # need opt gem5 variant with debug support
         h.extra_main_args.append('--debug-flags=SimBricksEthernet,SimBricksPci,EthernetAll,EthernetDesc')
         if internal:
             h.add_netdirect(net)

experiments/simbricks/experiment/experiment_environment.py

@@ -36,10 +36,12 @@ class ExpEnv(object):
         self.qemu_img_path = self.repodir + '/sims/external/qemu/build/qemu-img'
         self.qemu_path = self.repodir + '/sims/external/qemu/build/x86_64-softmmu/qemu-system-x86_64'
         self.qemu_kernel_path = self.repodir + '/images/bzImage'
-        self.gem5_path = self.repodir + '/sims/external/gem5/build/X86/gem5.fast'
         self.gem5_py_path = self.repodir + '/sims/external/gem5/configs/simbricks/simbricks.py'
         self.gem5_kernel_path = self.repodir + '/images/vmlinux'
 
+    def gem5_path(self, variant):
+        return self.repodir + '/sims/external/gem5/build/X86/gem5.' + variant
+
     def hdcopy_path(self, sim):
         return '%s/hdcopy.%s' % (self.workdir, sim.name)
 

experiments/simbricks/simulators.py

@@ -296,6 +296,7 @@ class Gem5Host(HostSim):
         super().__init__()
         self.extra_main_args = []
         self.extra_config_args = []
+        self.variant = 'fast'
 
     def set_config(self, nc):
         nc.sim = 'gem5'
@@ -315,7 +316,7 @@ class Gem5Host(HostSim):
         if env.create_cp:
             cpu_type = self.cpu_type_cp
 
-        cmd = f'{env.gem5_path} --outdir={env.gem5_outdir(self)} '
+        cmd = f'{env.gem5_path(self.variant)} --outdir={env.gem5_outdir(self)} '
         cmd += ' '.join(self.extra_main_args)
         cmd += (f' {env.gem5_py_path} --caches --l2cache --l3cache '
             '--l1d_size=32kB --l1i_size=32kB --l2_size=2MB --l3_size=32MB '