Hi all,
I am running Spec 2006 on X86 with the version gem5-stable-07352f119e48. I
am using multiprogram mode with syscall emulation. I am trying to compare
the IPC statistics for 2 cases:
1)Running benchmark A on a single core
2)Running 4 instances of benchmark A on a 4-core system with 1MB private L2
cashes.
All parameters are the same for the 2 runs except the number of cores.
I am expecting some IPC decrease for the 4-core case as the cores will
share the same system bus. However, for CactusADM and Soplex benchmarks, I
see higher IPC for case2 compared to case 1.
I look at the same phase of execution for both runs. I fastforward for 2
billion instructions and grab the ipc for each of the cores corresponding
to the next 100 million instructions in detailed mode.
I ll report some other statistics for CactusADM to give a better idea of
what is going on.
Case 1: ipc=0.664141, L2_overall _accesses=573746, L2_miss_rate=0.616
Case 2: cpu0_ipc=0.718562, cpu1_ipc= 0.720464, cpu2_ipc=0.717405, cpu3_ipc=
0.716513
L2_0_accesses=591607, L2_1_accesses=581846,
L2_2_accesses=568095, L2_3_accesses=561180, L2_0_missrate=0.452978,
L2_1_missrate=0.454510, L2_2_missrate=0.475646, L2_3_missrate=0.488171
Case 1:Running Time for 100M insts = 0.0716 sec
Case 2:Running Time for 100M insts = 0.066273 sec
Do you have any idea what could be the problem? Actually, is this a problem
or something expected for some benchmarks?
Best,
Fulya Kaplan
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