Hi Daniel, Thank you so much for your help. Finally, I can get different results in the stats file for bdi compression and null (without compression). However, I have the following wired results for lbm benchmark:
bdi system.l2.overall_miss_rate::total 0.620654 # miss rate for overall accesses system.switch_cpus.numCycles 14278894516 # number of cpu cycles simulated null system.l2.overall_miss_rate::total 0.620654 # miss rate for overall accesses system.switch_cpus.numCycles 14324960112 # number of cpu cycles simulated I cannot get why the number of cpu cycles decreases for bdi!?! Since miss rates for both of them are the same and also bdi has a decompression latency, I expect the number of cpu cycles would increase (I used following command line). My command line: ./build/X86/gem5.opt -d results/lbm/bdi/ ./configs/example/se.py -c /CPU2006/470.lbm/run/run_base_ref_m64-gcc.0000/lbm_base.m64-gcc --options="3000 reference.dat 0 0 /CPU2006/470.lbm/run/run_base_ref_m64-gcc.0000/100_100_130_ldc.of" --cpu-type=TimingSimpleCPU --cpu-clock=4GHz --num-cpus=1 --caches --l2cache --l1i_size=32kB --l1i_assoc=2 --l1d_size=32kB --l1d_assoc=2 --l2_size=2048kB --l2_assoc=16 --cacheline_size=64 --fast-forward=351000000 --maxinsts=1000000000 Many Thanks! Best, Pooneh On Fri, May 24, 2019 at 3:36 AM Daniel Carvalho <oda...@yahoo.com.br> wrote: > No idea; numCycles (and most other stats) should have been different if > you are using something other than an extremely simple (e.g., hello world) > workload. Check your configs to make sure you are running the ones you > desire. > > Regards, > Daniel > Em quinta-feira, 23 de maio de 2019 17:33:00 GMT+2, Pooneh Safayenikoo < > poneh.saf...@gmail.com> escreveu: > > > Hi Daniel, > > Thank you so much for your help. But, for all the benchmarks the > performance (based on "system.cpu.numCycles" and > "system.cpu.committedInsts" in stats file) of both BDI and uncompressed are > the same for me. Actually, all the metrics of cpu in the stats file are > same for both of them. Do you know why it happens for me due to different > miss rate for L2 cache? > > Many Thanks again! > > Best, > Pooneh > > On Thu, May 23, 2019 at 6:58 AM Daniel Carvalho <oda...@yahoo.com.br> > wrote: > > Hello Pooneh, > > You can check papers that discuss turning on and off compression (among > others), for common explanations of the negative influence of compression > in some workloads. Here is an extract of one of my simulation results both > for mcf and geo mean of all SPEC 2017 benchmarks: > > BDI on L3 > system.switch_cpus.ipc > 0.309029 # IPC: Instructions Per Cycle - 505.mcf_r > system.switch_cpus.ipc > 0.829107 # IPC: Instructions Per Cycle - Geo mean > > Uncompressed > system.switch_cpus.ipc > 0.310797 # IPC: Instructions Per Cycle - 505.mcf_r > system.switch_cpus.ipc > 0.823940 # IPC: Instructions Per Cycle - Geo mean > > As you can see, even though compression has a negative impact on the IPC > in mcf, overall it can generate improvements (similar results are seen > for the miss rate). > > Regards, > Daniel > Em quarta-feira, 22 de maio de 2019 05:50:22 GMT+2, Pooneh Safayenikoo < > poneh.saf...@gmail.com> escreveu: > > > Hi, > > I want to apply BDI compression on the L2 cache. So, I changed the config > file for the caches (gem5/configs/common/Caches.py) like following: > > class L1Cache(Cache): > tags = BaseSetAssoc() > compressor = NULL > class L2Cache(Cache): > tags = CompressedTags() > compressor = BDI() > > After that, I got the results for some SPEC benchmarks (I used a > configuration like BDI paper) to compare the L2 miss rate between this > compression and baseline (without applying BDI and CompressedTags). > But, miss rate increases a little for some benchmarks (like mcf and bzip). > Why BDI has higher L2 miss rate? I cannot make sense of it. > > Many thanks for any help! > > Best, > Pooneh > >
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