Gem5 has a command line argument --dual. This starts up 2 separate simulations (inside 1 process) where one is called the driver and the other is the 'real' test system. Since networking requires at least two systems, you usually use --dual when you want to test the network. Because gem5 is not yet multi-threaded (I think), both simulations end up using only 1 core. Hence, ideally this should result in a 2x slowdown. However, I'm seeing a lot more. That's what my question was about.
My single system simulations also take about 12-15 hours to complete. With detailed they take a lot longer (haven't fully completed a sim yet). Regards Guru On Mon, Aug 3, 2015 at 12:42 PM, Davesh Shingari <[email protected]> wrote: > Just to be sure,what do you mean by dual? > Do you mean 2 simulation or multiple core configuration? > ᐧ > > On Mon, Aug 3, 2015 at 9:39 AM, Guru Prasad <[email protected]> wrote: > >> Hi Davesh, just to clarify, is this with --dual? >> >> Regards >> Guru >> >> >> On Mon, Aug 3, 2015 at 12:38 PM, Davesh Shingari < >> [email protected]> wrote: >> >>> Hi Guru >>> >>> I am using Android on Gem5 for my work. When I use the simulation to >>> take checkpoint, then it takes around 12 - 15 hours to get checkpoint and >>> finish simulation. The simulation time is 32 seconds after the checkpoint. >>> But when I use that checkpoint along with detailed mode configuration and >>> full memory system, then it takes almost a week to complete. >>> ᐧ >>> >>> On Mon, Aug 3, 2015 at 9:23 AM, Guru Prasad <[email protected]> >>> wrote: >>> >>>> Ah I see. It sounds like the sort of like the hack we made for hdlcd >>>> where we read from physical memory directly. >>>> >>>> Thanks once again. I will try the options you've described. >>>> >>>> Regards >>>> Guru >>>> >>>> >>>> On Mon, Aug 3, 2015 at 12:19 PM, Andreas Hansson >>>> <[email protected]> wrote: >>>> > Hi Guru, >>>> > >>>> > 3 days for 20 seconds sounds way slower than it should be. >>>> > >>>> > Fast-mem is not replacing the DRAM controller, it bypasses the entire >>>> > memory system. In atomic we do not do any sensible timing simulation >>>> of >>>> > the controller in any case. >>>> > >>>> > The KVM CPU is only built if your system support it. Hence, you need >>>> to >>>> > build gem5 for ARM on an ARM system. A good reason to get an ARM >>>> server :-) >>>> > >>>> > Andreas >>>> > >>>> > On 03/08/2015 16:46, "gem5-users on behalf of Guru Prasad" >>>> > <[email protected] on behalf of [email protected]> >>>> wrote: >>>> > >>>> >>Hi Andreas, >>>> >> >>>> >>Thanks for the suggestions. It took about 3 days to simulate 20seconds >>>> >>under atomic. >>>> >>I don't know how to tell if interrupts are being lost. The kernel is >>>> >>not complaining about anything on kmsg. >>>> >>I will try atomic with --fast-mem. Currently, I've been using >>>> >>lpddr3_1600_x32 >>>> >> >>>> >>I don't think I have KvmArmCPU available. I will try the same with the >>>> >>latest. >>>> >>Is using KvmArmCPU as simple as just saying --cpu-type=...? >>>> >>I ask this because --list-cpu-types for my current version only >>>> displays >>>> >> timing => TimingSimpleCPU >>>> >> detailed => DerivO3CPU >>>> >> atomic => AtomicSimpleCPU >>>> >> minor => MinorCPU >>>> >> >>>> >> >>>> >>Regards >>>> >>Guru >>>> >> >>>> >>On Mon, Aug 3, 2015 at 11:33 AM, Andreas Hansson >>>> >><[email protected]> wrote: >>>> >>> Hi Guru, >>>> >>> >>>> >>> To speed things up, here are some options: >>>> >>> >>>> >>> 1. Use atomic to get the point of interest, then take a checkpoint. >>>> Is >>>> >>> this what you are doing? >>>> >>> >>>> >>> 2. For the above, run with --fast-mem since you’re not warming any >>>> >>>caches >>>> >>> anyways. >>>> >>> >>>> >>> 3. If possible, use the KvmArmCPU instead of (1). This should give >>>> you a >>>> >>> significant boost. >>>> >>> >>>> >>> If the amount of work is constant, than running with dual should not >>>> >>>slow >>>> >>> things down. If you’re seeing a slow down, then perhaps something >>>> odd is >>>> >>> going on in the simulation (interrupts getting lost etc). Have you >>>> tried >>>> >>> with the latest trunk? >>>> >>> >>>> >>> Andreas >>>> >>> >>>> >>> >>>> >>> On 03/08/2015 16:16, "gem5-users on behalf of Guru Prasad" >>>> >>> <[email protected] on behalf of [email protected]> >>>> wrote: >>>> >>> >>>> >>>>Hi, >>>> >>>> >>>> >>>>Recently we've been trying to run some experiments with the network. >>>> >>>>To do so, we've been using dual simulations. So far, we've been able >>>> >>>>to get away with running two simulations booting barebones linux >>>> with >>>> >>>>just a shell. However, our real workload is BBench and so we need to >>>> >>>>boot a full Android image. >>>> >>>> >>>> >>>>A single simulation of full Android takes us about ~12hours to boot. >>>> >>>>However under dual, its been about 3 days and has so far simulated >>>> >>>>only ~20seconds. Is there any way to speed up the simulation? Is >>>> there >>>> >>>>any way we can stitch two single simulations together (initial loss >>>> of >>>> >>>>time on drivesys is acceptable). >>>> >>>> >>>> >>>>Currently we're on revision e179497451. >>>> >>>> >>>> >>>>Regards >>>> >>>>Guru >>>> >>>>_______________________________________________ >>>> >>>>gem5-users mailing list >>>> >>>>[email protected] >>>> >>>>http://m5sim.org/cgi-bin/mailman/listinfo/gem5-users >>>> >>> >>>> >>> >>>> >>> -- 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 >>>> > >>>> > >>>> > -- 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 >>>> >>> >>> >>> >>> -- >>> Have a great day! >>> >>> Thanks and Warm Regards >>> Davesh Shingari >>> Master's in Computer Engineering [EE] >>> Arizona State University >>> >>> [email protected] >>> >>> _______________________________________________ >>> 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 >> > > > > -- > Have a great day! > > Thanks and Warm Regards > Davesh Shingari > Master's in Computer Engineering [EE] > Arizona State University > > [email protected] > > _______________________________________________ > gem5-users mailing list > [email protected] > http://m5sim.org/cgi-bin/mailman/listinfo/gem5-users >
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