Hi,
I'm experiencing some problems that I currently am attributing to
restoring from a checkpoint, then switching to an arm_detailed CPU
(O3_ARM_v7a_3). I first noticed the problem due to my committed
instruction counts not lining up correctly between different CPUs for a
benchmark I'm running (by roughly 170M instructions). The stats below are
reset right before running the benchmark, then dumped afterwards:
Atomic CPU (no checkpoint restore): system.cpu.numInsts = 476085242
Detailed CPU (no checkpoint restore): system.cpu.committedInsts =
476128320
system.cpu.fetch.Insts = 478463491
Arm_detailed CPU (checkpoint restore):
system.switch_cpus_1.committedInsts = 646468886
system.switch_cpus_1.fetch.Insts = 660969371
Arm_detailed CPU (no checkpoint restore): system.cpu.committedInsts =
476107801
system.cpu.fetch.Insts = 491814681
I included both the committed and fetched instructions, to see if the
problem is with fetchs getting counted as committed even if they are not
(i.e. insts not getting squashed). It does not seem like that is the case
from the stats above...as the arm_detailed run without a checkpoint has
roughly the same difference between fetched/committed instructions. I
noticed that the switch arm_detailed cpu when restoring from a checkpoint
lacks both a icache and dcache as children, but I read in a previous post
that they are connected to fetch/iew respectively, so this is probably not
the issue. I assume it's just not shown explicitly in the config.ini
file...
I'm running a test right now to see if switching to a regular
DerivO3CPU has the same issue. Regardless of its results, does anyone have
any idea why I'm seeing roughly 170M more committed instructions in the
arm_detailed CPU run when I restore from a checkpoint? I've attached my
config file from the arm_detailed with checkpoint run for reference.
Here's the run command for when I use a checkpoint:
build/ARM/gem5.fast -d [dir] configs/example/fs.py -b [benchmark] -r 1
--checkpoint-dir=[chkpt-dir] --caches -s
Lastly, I'm running off of revision 8813 from 2/3/12. Let me know if
you need anymore info (i.e. stats).
Thanks,
Andrew
config.ini
Description: Binary data
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