Anybody?

On Tue, Nov 20, 2018 at 12:28 AM Amine Marref <[email protected]> wrote:

> Hello,
>
> I am trying to understand some of the timing behaviour of a multi-threaded
> application. I am running gem5 in FS mode and I can obtain two useful files
> "stats.txt" and "system.tasks.txt". Throughout the lines of the two files,
> I could find three ways of referring to a cpu/core: (i) "cpu" suffixed with
> a natural number (cpuN), (ii) "cpus" suffixed with a natural number
> (cpusN), and (iii) "cpu_id" equals some natural number (cpu_id=N).
>
> The following are (non-contiguous) lines from the "stats.txt" output file.
> system.cpu0.dtb.hits
> 6                       # DTB hits
> system.cpu1.pwrStateResidencyTicks::OFF
> 203472000                       # Cumulative time (in ticks) in various
> power states
> system.cpu2.itb.inst_hits
> 0                       # ITB inst hits
> system.cpu3.itb.flush_tlb
> 2                       # Number of times complete TLB was flushed
> system.switch_cpus0.fetch.rateDist::samples       312140
>    # Number of instructions fetched each cycle (Total)
> system.switch_cpus1.rob.rob_reads
> 0                       # The number of ROB reads
> system.switch_cpus2.iew.iewIdleCycles
> 0                       # Number of cycles IEW is idle
> system.switch_cpus3.itb.write_accesses
> 0                       # DTB write accesses
>
> The following are lines from the "systems.tasks.txt" output file.
> tick=3203692196500 5 cpu_id=0 next_pid=1107 next_tgid=1107
> next_task=runscript
> tick=3203956858500 6 cpu_id=0 next_pid=1 next_tgid=1 next_task=init
> tick=3204033514000 3 cpu_id=0 next_pid=-1 next_tgid=-1 next_task=kernel
>
> My understanding is that "cpuN" in the "stats.txt" file refers to [0..N]
> processor cpus/cores specified by the flag "-n N" that is passed to the
> simulation script "fs.py". My guess is that "cpusN" refers to the same
> entity but what is the "s" doing there? To mean "switch"? Finally, from my
> reading around, it looks like "cpu_id=N" is not related to the cpus/cores
> used to simulate a program but rather to the cpu model used in simulation
> e.g. "--cpu-type=O3_ARM_v7a_3" has "cpu_id=0".
>
> My question finally is: "is my understanding of the meaning of the three
> cpu entities above correct"?
>
> Thanks,
> Amine.
>
> --
> marref.org
>
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