Hello, everyone, Now I am using M5 to simulation Spec CPU2006, I have got some in-consistence statistics, Hope someone could give reasonable explanations.
I simulated benchmark 401.bzip2 with 1 billion instructions, and only one cpu core in SE mode. The simulations cmd is here: build/ALPHA_SE/m5.opt /configs/example/se_cpu2006.py -n1 --detailed --caches --l2cache --maxinsts 1000000000 -b bzip2 [1] The first question is there are two commit parameters showing below. According to their names, I guess they are both meaning how many are instruction are committed. But there number are different, any reason? I want to simulated 1,000,000,000 insts. system.cpu.commit.COM:count 1001844707 # Number of instructions committed system.cpu.committedInsts 1000000000 # Number of Instructions Simulated system.cpu.committedInsts_total 1000000000 # Number of Instructions Simulated Simply, my question is why "system.cpu.commit.COM:count != system.cpu.committedInsts"? what is the difference come from? [2]The second question is why the # of memory loads inst committed is not equal to L1 dcache ReadReq demand access? why the # of memory reference inst committed is not equal to L1 dcache overall demand access? system.cpu.commit.COM:loads 235487280 # Number of loads committed system.cpu.commit.COM:membars 70 # Number of memory barriers committed system.cpu.commit.COM:refs 328322098 # Number of memory references committed system.cpu.dcache.ReadReq_accesses 279749292 # number of ReadReq accesses(hits+misses) system.cpu.dcache.WriteReq_accesses 92768715 # number of WriteReq accesses(hits+misses) Simply, my question is why "system.cpu.commit.COM:loads !=system.cpu.dcache.ReadReq_accesses"? where the extra dcache ReadReq come from? One of my guess is the difference is from some speculation instructions, there load instructions finally does not commit, but I am not sure whether all two number difference is coming from un-committed load instruction? [3]The third question is how do we define idleCycles? Is that mean there is no operation in any functional unit due to data dependency or waiting loading data from memory? system.cpu.idleCycles 7409255 # Total number of cycles that the CPU has spent unscheduled due to idling Many thanks in advance Dawei
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