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-users@gem5.org> > Sent: 15 March 2021 16:26 > To: gem5-users@gem5.org > Cc: Farhad Yusufali <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> , 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. _______________________________________________ gem5-users mailing list -- gem5-users@gem5.org To unsubscribe send an email to gem5-users-le...@gem5.org %(web_page_url)slistinfo%(cgiext)s/%(_internal_name)s
