Add a set of scripts to automatically test checkpointing in the
regression framework. The checkpointing tests are similar to the
switcheroo tests, but instead of switching between CPUs, they
checkpoint the system and restore from the checkpoint again. This is
done at regular intervals, typically while booting Linux.
The implementation is fairly straight forward, with the exception that
we have to work around gem5's inability to restore from a checkpoint
after a system has been instantiated. We work around this by forking
off child processes that does the actual simulation and never
instantiate a system in the parent process unless a maximum checkpoint
count is reached (in which case we just simulate the system to
completion in the parent).
Checkpoint testing is currently only enabled 32- and 64-bit ARM
systems using atomic CPUs.
Note: An unfortunate side-effect of forking is that every new process
will overwrite the stats and terminal output from the previous
process. This means that the output directory only contains data from
the last checkpoint.
Changes due to speculative execution of an unaligned PC, introduction
of TLB stats, changes and re-work of the prefetcher, and the
introduction of rank-wise refresh in the DRAM controller.
As a result of the fixes, the full-system dual-core ARM regressions
are slightly changed. Hopefully this also means there will no longer
be any discrepancies between the results observed on different hosts.
This patch bumps the stats to reflect the addition of the snoop filter
and snoop stats, the change from bus to crossbar, and the updates to
the ARM regressions that are now using a different CPU and cache
configuration. Lastly, some minor changes are expected due to the
activation cleanup of the CPUs.
This patch changes the perlbmk regression script from the large to the
medium dataset to reduce the regression run time. For all ISAs and CPU
models, the total perlbmk host CPU time with the large dataset is
roughly 12 hours (constituting >30% of the total regression host
time). There is, most likely, almost no added value in terms of code
coverage for this rather excessive run time.
This patch avoids building the 'inorder' CPU model for any permutation
of ALPHA, and also removes the ALPHA regressions using the 'inorder'
CPU. The 'minor' CPU is already providing a broader test coverage.
Only printing one rather than two args for the ignored syscall
warning means the count of register accesses has changed on
a few runs. Oddly only Alpha Tru64 seems to have any ignored
syscalls in the regression tests.
Mostly small differences in total ticks, but O3 stall causes
shifted significantly.
30.eon does speed up by ~6% on Alpha and ARM, and 50.vortex
by 4.5% on ARM. At the other extreme, X86 70.twolf is 0.8%
slower.
