Hi Gem Users,
I run a simple program (same binary) on both gem5 (aarch64) & ARM Juno board.
Below is the code:
int main(void)
{
int i,y;
for (i=0;i<100;i++)
y++;
return 0;
}
However, number of instruction reported by gem5 & linux perf tool for
the same program binary is not same, or not even comparable.
Please give some insight on this.
num of inst reported by perf = 1096938
num of inst reported by gem5 = 10102135
Program binary name - hello
command used on Juno:
sudo perf stat -C 1 -e cpu-cycles,instructions taskset -c 1 ./hello
1674642 cpu-cycles [99.94%]
1096938 instructions # 0.66 insns per cycle (1096938/1674642=0.66)
Command used on gem5:
build/ARM/gem5.opt -d /home/vpathak/gem5_git/gem5/m5out_hello_ash
configs/example/fs.py \
--checkpoint-restore=1 --restore-with-cpu=DerivO3CPU
--script=/home/vpathak/gem5_git/gem5/configs/boot/nas.rcS \
--kernel=/home/vpathak/gem5_git/full-system-images/binaries/vmlinux.aarch64.20140821
--machine-type=VExpress_EMM64 \
--dtb-file=/home/vpathak/gem5_git/full-system-images/binaries/vexpress.aarch64.20140821.dtb
\
--disk-image=/home/vpathak/gem5_git/full-system-images/disks/aarch64-ubuntu-trusty-headless.img
\
--cpu-type=DerivO3CPU --arm-iset=aarch64 --num-cpus=1
--cpu-clock=3GHz --caches --l2cache --l3cache
nas.rcS:
/sbin/m5 resetstats
/opt/native/hello
/sbin/m5 exit
system.cpu.committedInsts 10102135
system.cpu.numCycles 22634230
system.cpu.ipc 0.446321 (10102135/22634230 = 0.446321)
Thanks for your time in advance.
--
with regards,
Virendra Kumar Pathak
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