For anyone who would like to share one L1 cache among multiple cpus I have found a possible solution that seems to work:
1) I modified the ruby protocol specific python config file (for example MOESI_CMP_direcory.py in /gem5/configs/ruby) to create just one L1 cache, one controller and one sequencer 2) In ruby_fs.py I connected each cpu's cache ports to the one L1 ruby sequencer created in step 1 In this way I successfully simulated fft splash2 benchmark in ALPHA fs mode. Pavlos On Fri, 2012-11-23 at 19:31 +0200, Pavlos Maniotis wrote: > I would like to experiment with these two different scenarios: > > 1) 4 CPUs at 2GHz sharing 1 L1 cache at 2GHz > > vs > > 2) 4 CPUs at 2GHz sharing 1 L1 cache at 8GHz > > I am not sure if this would work with ruby but if not I could > try with Simple Memory Module. > > Do you have any suggestions on which code to modify? > I am new to gem5 and I am trying to get familiar with it. > > Pavlos > > On Fri, 2012-11-23 at 17:06 +0000, Jack Harvard wrote: > > Why not, just put a bus in between CPUs and L1? But why would you do > > so? > > > > Jack Harvard > > > > > > On Fri, Nov 23, 2012 at 4:06 PM, Pavlos Maniotis > > <[email protected]> wrote: > > Thanks Andreas, > > > > I would like to ask you one more thing: > > Do you believe it is feasible to simulate > > a system with L1 shared cache among cpus (either with ruby or > > with > > Classic Memory System)? I have searched the mailing list but > > I couldn't find some helpful info. > > > > On Fri, 2012-11-23 at 14:38 +0000, Andreas Hansson wrote: > > > Hi Pavlos, > > > > > > There have been numerous discussions around the CPU to L1 > > > bandwidth/latency, and by default it is not limited (i.e. it > > is just two > > > ports connected together). IF you want (and as Steve has > > previously > > > pointed out) you can insert a CoherentBus between the CPU > > and L1 if you > > > want, but you will have to change the config scripts. > > > > > > Good luck. > > > > > > Andreas > > > > > > On 23/11/2012 14:34, "Pavlos Maniotis" > > <[email protected]> wrote: > > > > > > >Hi Andreas, > > > > > > > >Thanks for the info, does it also apply for the Classic > > Memory System? > > > >I was thinking that there was a bus between CPU and L1 with > > some width > > > >and some frequency, for example 64bit and 2GHz. I wanted to > > test two > > > >different systems and compare the performance between them: > > > > > > > >1) CPU (2GHz) <--------[bus 64 width, 2GHz]---------> L1 > > (2GHz) ->to L2 > > > >2) CPU (2GHz) <--------[bus 32 width, 4GHz]---------> L1 > > (4GHz) ->to L2 > > > > > > > >Do you think that I cannot use gem5 to do this experiment? > > > > > > > >Thanks again, > > > >Pavlos > > > >On Fri, 2012-11-23 at 14:14 +0000, Andreas Hansson wrote: > > > >> Hi Pavlos, > > > >> > > > >> There is no bus between the CPU core and the L1, just a > > "port" > > > >>connection. > > > >> The PIO bus is only used for PIO, and should not have a > > great impact on > > > >> your benchmark unless it is very I/O intensive. > > > >> > > > >> Andreas > > > >> > > > >> On 23/11/2012 12:29, "Pavlos Maniotis" > > <[email protected]> wrote: > > > >> > > > >> >Hello everyone, > > > >> > > > > >> >I use ruby (MOESI_CMP_directory) and I want to simulate > > a system > > > >> >with one CPU (frequency=2GHz) and L1 and L2 caches > > (frequency=4GHz). > > > >> >I also want the bus between cpu and cache > > > >> >to run at 4GHz with width 32 bits. So I have to set the > > cpu > > > >> >frequency equal to 4GHz (ruby_fs.py -> CPUClass.clock = > > '2GHz') > > > >> >and ruby frequency equal to 2GHz > > > >> >(Ruby.py -> system.ruby = RubySystem(clock = 4, > > > >> > stats_filename = > > options.ruby_stats, > > > >> > no_mem_vec = > > options.use_map)). > > > >> > > > > >> >I suppose these changes are right, my main concern is: > > > >> > > > > >> >Do I have to change system.piobus frequency > > > >> >to 4GHz and width to 4 bytes (file FSConfig.py, function > > > >> >makeLinuxAlphaRubySystem)? > > > >> >Is this the bus between cpu and L1 cache? If it is not > > > >> >how can I configure the bus between L1 and CPU? > > > >> > > > > >> >I am little bit confused about the interconnection > > system. > > > >> > > > > >> >Thanks in advance for any help, > > > >> >Pavlos > > > >> > > > > >> > > > > >> >_______________________________________________ > > > >> >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. > > > >> > > > >> _______________________________________________ > > > >> 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. > > > > > > _______________________________________________ > > > 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 > > > > > > > > _______________________________________________ > > 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
