The output from the switcheroo tests is voluminous and
(because it includes timestamps) highly sensitive to
minor changes, leading to extremely large updates to the
reference outputs. This patch addresses this problem
by suppressing output from the tests. An internal
parameter can be set to enable the output. Wiring that
up to a command-line flag (perhaps even the rudimantary
-v/-q options in m5/main.py) is left for future work.
CPU switching consists of the following steps:
1. Drain the system
2. Switch out old CPUs (cpu.switchOut())
3. Change the system timing mode to the mode the new CPUs require
4. Flush caches if switching to hardware virtualization
5. Inform new CPUs of the handover (cpu.takeOverFrom())
6. Resume the system
m5.switchCpus() previously only did step 2 & 5. Since information
about the new processors' memory system requirements is now exposed,
do all of the steps above.
This patch adds automatic memory system switching and flush (if
needed) to switchCpus(). Additionally, it adds optional draining to
switchCpus(). This has the following implications:
* changeToTiming and changeToAtomic are no longer needed, so they have
been removed.
* changeMemoryMode is only used internally, so it is has been renamed
to be private.
* switchCpus requires a reference to the system containing the CPUs as
its first parameter.
WARNING: This changeset breaks compatibility with existing
configuration scripts since it changes the signature of
m5.switchCpus().
This changeset adds a set of tests that stress the CPU switching
code. It adds the following test configurations:
* tsunami-switcheroo-full -- Alpha system (atomic, timing, O3)
* realview-switcheroo-atomic -- ARM system (atomic<->atomic)
* realview-switcheroo-timing -- ARM system (timing<->timing)
* realview-switcheroo-o3 -- ARM system (O3<->O3)
* realview-switcheroo-full -- ARM system (atomic, timing, O3)
Reference data is provided for the 10.linux-boot test case. All of the
tests trigger a CPU switch once per millisecond during the boot
process.
The in-order CPU model was not included in any of the tests as it does
not support CPU handover.
