Even with x86 you should be seeing deterministic results. If you are regularly seeing inconsistencies, you can try running two copies with debug tracing (I suggest Exec,ExecMacro,Cache as a starting set of flags) and comparing their output with util/tracdiff to see where they diverge.
Steve On Thu, Aug 13, 2015 at 9:44 AM Andreas Hansson <[email protected]> wrote: > Hi Prathap, > > That sounds very odd and should not happen unless the workload itself is > somehow random. What is it you are running? Are you sure you’re running > exactly the same thing? > > If it does indeed vary then it would be good if you can track down why by > running two simulations in lock-step and determining where they diverge. > > We regularly run the ARM regressions with UBSan to ensure there is no > undefined behaviour in the simulator. I know that for X86 there are quite a > few warnings from UBSan, so that could be a reason if you’re using x86. > > Andreas > > From: gem5-users <[email protected]> on behalf of Prathap > Kolakkampadath <[email protected]> > Reply-To: gem5 users mailing list <[email protected]> > Date: Thursday, 13 August 2015 09:11 > To: gem5 users mailing list <[email protected]> > Subject: [gem5-users] Sources of In-determinism in Full System Simulators > > Hello User, > > I am running a benchmark in gem5 full system mode. Checkpoint is created > in atomic mode and then switches to detailed mode before starting the > benchmark. On repeated runs of the benchmark from same checkpoint, the > number of memory requests arriving at DRAM banks differs; up-to 5% > variation. Can someone point out, what could be the sources of > in-determinism? > > > Thanks, > Prathap > > -- 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. > > ARM Limited, Registered office 110 Fulbourn Road, Cambridge CB1 9NJ, > Registered in England & Wales, Company No: 2557590 > ARM Holdings plc, Registered office 110 Fulbourn Road, Cambridge CB1 9NJ, > Registered in England & Wales, Company No: 2548782 > _______________________________________________ > gem5-users mailing list > [email protected] > http://m5sim.org/cgi-bin/mailman/listinfo/gem5-users
_______________________________________________ gem5-users mailing list [email protected] http://m5sim.org/cgi-bin/mailman/listinfo/gem5-users
