[gem5-users] Gem5 freezing with x86 timing cpu

[George Michelogiannakis via gem5-users]

Hi all,

I have this weird problem where gem5 starts executing a benchmark (some parsec 
and some others) or starts booting in FS mode but then just freezes. I was 
wondering how you would recommend getting to the bottom of this. Can I figure 
out what it's doing? I know I can attach a debugger but this happens after many 
hours so with the debugger it'll be even slower. Also, I'm not sure if gdb's 
backtrace function will really help me.

This happens with the latest development and stable versions.

Here is how I try to run gem5 for FS (similar for SE):

./build/X86_MESI_Two_Level/gem5.opt --remote-gdb-port=0 
--outdir=results/$1_none_x86_dir --dump-config=$1_config --redirect-stdout 
--redirect-stderr --stdout-file=m5sim.out --stderr-file=$1_err 
--stats-file=$1_stats configs/example/fs.py --script=./runscripts/$1 
--disk-image=all_benchmarks.img --kernel=x86_64-vmlinux-2.6.28.4-smp 
--cpu-type=timing --caches --prefetcher-type=none --l2cache --sys-clock=2GHz 
--cpu-clock=2GHz --num-dirs=8 --num-l2caches=8 --num-l3caches=4 --l2_size=4MB 
--l3_size=32MB --l1d_assoc=2 --l1i_assoc=2 --l2_assoc=8 --l3_assoc=16 
--mem-type=DDR3_1600_x64 --cacheline_size=64 --checkpoint-dir=checkpoints 
--num-cpus=64

I tried running with atomic cpus and that seems to work, but with x86 i can't 
restore with a different type cpu nor use switchcpu during execution as I 
understand current limitations. Plus i need timing for my SE runs.

The only modification I did really is to move the prefetcher to the L2, by 
editing CacheConfig.py such as:

        if options.prefetcher_type == "stride":

            system.l2.prefetch_on_access = 'true'
            system.l2.prefetcher = StridePrefetcher(degree=8, latency=1)
        elif options.prefetcher_type == "tagged":
            system.l2.prefetch_on_access = 'true'
            system.l2.prefetcher = TaggedPrefetcher(degree=8, latency=1)
        elif options.prefetcher_type == "none":
            system.l2.prefetch_on_access = 'false'
        else:
            print "Unknown Prefetcher Type"
            sys.exit(1)


Freezing happens with all prefetchers though. Notice that I don't use Ruby.

Thank you in advance,
  George M

_______________________________________________
gem5-users mailing list
gem5-users@gem5.org
http://m5sim.org/cgi-bin/mailman/listinfo/gem5-users