That’s very helpful, thanks a lot! Best, Farhad
On Mar 15, 2021, at 1:32 PM, Giacomo Travaglini <giacomo.travagl...@arm.com<mailto:giacomo.travagl...@arm.com>> wrote: EXTERNAL EMAIL: Yeah, this is a quirkiness of gem5. I have tried to address it some time ago [1]; I should probably go back and rebase the patchset. Basically the numOp, by being a Counter (and not a Stat) doesn't get reset every time you reset stats. So the numOp is the total number of ops since the beginning of the simulation, whereas committedOp is the real indication of committed ops in the region of interest (as it can be reset). My advice is to simply look at committedOp if you just want to know executed ops in the region of interest Kind Regards Giacomo [1]: https://gem5-review.googlesource.com/c/public/gem5/+/25303 -----Original Message----- From: Farhad Yusufali <farhad.yusuf...@mail.utoronto.ca<mailto:farhad.yusuf...@mail.utoronto.ca>> Sent: 15 March 2021 17:22 To: Giacomo Travaglini <giacomo.travagl...@arm.com<mailto:giacomo.travagl...@arm.com>> Cc: gem5 users mailing list <gem5-users@gem5.org<mailto:gem5-users@gem5.org>> Subject: Re: Simulated vs Committed Ops Hi Giacomo, I only execute a single workload every time I run a simulation, so there are no interactions between different workloads. I do reset my stats at the beginning of the region of interest of my workload though (using a pseudo-instruction). Thanks, Farhad On Mar 15, 2021, at 12:56 PM, Giacomo Travaglini <giacomo.travagl...@arm.com<mailto:giacomo.travagl...@arm.com> <mailto:giacomo.travagl...@arm.com> > wrote: EXTERNAL EMAIL: Hi Farhad, Quick question: are you resetting the stats between one workload and the other? Kind Regards Giacomo -----Original Message----- From: Farhad Yusufali via gem5-users <gem5- us...@gem5.org<mailto:us...@gem5.org> <mailto:gem5-users@gem5.org> > Sent: 15 March 2021 16:26 To: gem5-users@gem5.org<mailto:gem5-users@gem5.org> <mailto:gem5-users@gem5.org> Cc: Farhad Yusufali <farhad.yusuf...@mail.utoronto.ca<mailto:farhad.yusuf...@mail.utoronto.ca> <mailto:farhad.yusuf...@mail.utoronto.ca> > Subject: [gem5-users] Simulated vs Committed Ops Hello all, I’m trying to figure out the difference between two stats - simOps and system.cpu.commit.committedOps. I’m using a 4-wide single DerivO3CPU CPU, running serial workloads (i.e. no threads). In src/cpu/o3/cpu.cc<http://cpu.cc/> <http://cpu.cc/> <http://cpu.cc<http://cpu.cc/> <http://cpu.cc/> > , in the instDone function, I found the following code that is executed every time an instruction is committed: thread[tid]->numOp++; thread[tid]->numOps++; committedOps[tid]++; As you can see, both committedOps and numOp is incremented once for every op committed. In the same file, in the totalOps function, the numOp values across different threads are accumulated to return a total op count for the entire core: template <class Impl> Counter FullO3CPU<Impl>::totalOps() const { Counter total(0); ThreadID size = thread.size(); for (ThreadID i = 0; i < size; i++) { total += thread[i]->numOp; } return total; } Finally, in src/cpu/base.hh, in the BaseCPU class, there is a function, numSimulatedOps that coalesces op counts across CPUs: static Counter numSimulatedOps() { Counter total = 0; int size = cpuList.size(); for (int i = 0; i < size; ++i) total += cpuList[i]->totalOps(); return total; } This total value is used to generate the simOps stat. To summarize, every time an op is commited, both committedOps and numOp are incremented. committedOps is dumped out using the system.cpu.commit.committedOps stat, while numOp is accumulated across both threads and CPUs and then dumped out using the simOps stat. Since I’m using a single CPU with a single thread, I would expect both stats to be identical, however they end up being vastly different (sometimes by over a factor of 10) (simOps is usually larger). Does anyone have any insight into why this could be happening? Thanks, Farhad IMPORTANT NOTICE: The contents of this email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please notify the sender immediately and do not disclose the contents to any other person, use it for any purpose, or store or copy the information in any medium. Thank you. IMPORTANT NOTICE: The contents of this email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please notify the sender immediately and do not disclose the contents to any other person, use it for any purpose, or store or copy the information in any medium. Thank you.
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