How to use the example scripts?

[mytbk]

I'm currently doing some research on defending against Spectre. I'd like to reproduce the results of InvisiSpec. I'm new to gem5. Sorry for asking you about using the experiment environment.

I saw in the example script run_spec_from_ckpt.sh that you use --checkpoint-restore=10000000000. Does this mean the skip the first 10 billion instructions; then, we simulate 1 billion instructions in the paper? And if I use --take-checkpoints=10000000000 to take a checkpoint running the unsafe baseline processor, can I use this checkpoint to run on other processors like IS-Sp?

[mjyan0720]

Sorry for replying late.

Yes, you can use different configurations IS-Sp/Fu-Sp etc on the same checkpoints. You can generate a checkpoint using "--take-checkpoints=N --at-instruction" if you want to skip the first N instructions. Please consult complete commands you should use from the gem5 mannual website. Then you can do detailed simulation using "--checkpoint-restore=N --at-instruction --maxinsts=M" if you want to do detailed simulation for M instructions. Hope it helps.

[mytbk]

Thanks. I'm now using AtomicSimpleCPU to make a checkpoint. I think it's also needed to set the ruby cache parameters, I think the configuration in the paper is:

diff --git a/configs/ruby/MESI_Two_Level.py b/configs/ruby/MESI_Two_Level.py
index 65d711e5e..44118be2d 100644
--- a/configs/ruby/MESI_Two_Level.py
+++ b/configs/ruby/MESI_Two_Level.py
@@ -37,8 +37,13 @@ from Ruby import send_evicts
 #
 # Declare caches used by the protocol
 #
-class L1Cache(RubyCache): pass
-class L2Cache(RubyCache): pass
+class L1Cache(RubyCache):
+    tagAccessLatency = 1
+    dataAccessLatency = 1
+
+class L2Cache(RubyCache):
+    tagAccessLatency = 8
+    dataAccessLatency = 8
 
 def define_options(parser):
     return