I see. Thank you for the info. -Rizwana
On Thursday, August 6, 2015, Andreas Hansson <[email protected]> wrote: > Hi Rizwana, > > The KVM CPU is really for fast forwarding. When you use it, you will get > no stats, and no parts of the memory system are exercised. > > You could envision building up a sampling-based methodology. In fact, > there has been some work done already, as presented at the ISCA gem5 > workshop. > > Andreas > > From: gem5-users <[email protected] > <javascript:_e(%7B%7D,'cvml','[email protected]');>> on behalf > of Rizwana Begum <[email protected] > <javascript:_e(%7B%7D,'cvml','[email protected]');>> > Reply-To: gem5 users mailing list <[email protected] > <javascript:_e(%7B%7D,'cvml','[email protected]');>> > Date: Wednesday, 5 August 2015 20:35 > To: gem5 users mailing list <[email protected] > <javascript:_e(%7B%7D,'cvml','[email protected]');>> > Subject: Re: [gem5-users] Reducing time taken by dual simulations > > Hello Andreas, > > We are considering to use ArmKvmCPU. I have a couple of questions > regarding its simulation methodology. From my understanding so far, KVM is > a good way to speedup simulations by switching between virtual (faster) and > simulated CPU. So, I am wondering if we can rely on all Gem5 stats that > will be reported after the simulation? Will running an arm_detailed CPU and > ArmKvmCPU result in similar stats? Also, does KVM CPU use dram controller > from Gem5 to simulate memory or it uses host physical memory? > > Thanks, > -Rizwana > > On Mon, Aug 3, 2015 at 3:31 PM, Davesh Shingari <[email protected] > <javascript:_e(%7B%7D,'cvml','[email protected]');>> wrote: > >> Thanks a lot for clarification. >> I didn't know about that. >> ᐧ >> >> On Mon, Aug 3, 2015 at 9:47 AM, Guru Prasad <[email protected] >> <javascript:_e(%7B%7D,'cvml','[email protected]');>> wrote: >> >>> 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] >>> <javascript:_e(%7B%7D,'cvml','[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] >>>> <javascript:_e(%7B%7D,'cvml','[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] >>>>> <javascript:_e(%7B%7D,'cvml','[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] >>>>>> <javascript:_e(%7B%7D,'cvml','[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] >>>>>>> <javascript:_e(%7B%7D,'cvml','[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] >>>>>>> <javascript:_e(%7B%7D,'cvml','[email protected]');> on >>>>>>> behalf of [email protected] >>>>>>> <javascript:_e(%7B%7D,'cvml','[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] >>>>>>> <javascript:_e(%7B%7D,'cvml','[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] >>>>>>> <javascript:_e(%7B%7D,'cvml','[email protected]');> on >>>>>>> behalf of [email protected] >>>>>>> <javascript:_e(%7B%7D,'cvml','[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] >>>>>>> <javascript:_e(%7B%7D,'cvml','[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] >>>>>>> <javascript:_e(%7B%7D,'cvml','[email protected]');> >>>>>>> >>> http://m5sim.org/cgi-bin/mailman/listinfo/gem5-users >>>>>>> >>_______________________________________________ >>>>>>> >>gem5-users mailing list >>>>>>> >>[email protected] >>>>>>> <javascript:_e(%7B%7D,'cvml','[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] >>>>>>> <javascript:_e(%7B%7D,'cvml','[email protected]');> >>>>>>> > http://m5sim.org/cgi-bin/mailman/listinfo/gem5-users >>>>>>> _______________________________________________ >>>>>>> gem5-users mailing list >>>>>>> [email protected] >>>>>>> <javascript:_e(%7B%7D,'cvml','[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] >>>>>> <javascript:_e(%7B%7D,'cvml','[email protected]');> >>>>>> >>>>>> _______________________________________________ >>>>>> gem5-users mailing list >>>>>> [email protected] >>>>>> <javascript:_e(%7B%7D,'cvml','[email protected]');> >>>>>> http://m5sim.org/cgi-bin/mailman/listinfo/gem5-users >>>>>> >>>>> >>>>> >>>>> _______________________________________________ >>>>> gem5-users mailing list >>>>> [email protected] >>>>> <javascript:_e(%7B%7D,'cvml','[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] >>>> <javascript:_e(%7B%7D,'cvml','[email protected]');> >>>> >>>> _______________________________________________ >>>> gem5-users mailing list >>>> [email protected] >>>> <javascript:_e(%7B%7D,'cvml','[email protected]');> >>>> http://m5sim.org/cgi-bin/mailman/listinfo/gem5-users >>>> >>> >>> >>> _______________________________________________ >>> gem5-users mailing list >>> [email protected] >>> <javascript:_e(%7B%7D,'cvml','[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] >> <javascript:_e(%7B%7D,'cvml','[email protected]');> >> >> _______________________________________________ >> gem5-users mailing list >> [email protected] <javascript:_e(%7B%7D,'cvml','[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 >
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