Hi Jae-Eon, Thanks very much for your suggestion! The method seams very attractive and helpful. I’ll take it and tell the progress as soon as I get it.
Regards, Chao On Sep 18, 2014, at 1:39 PM, Jae-Eon Jo via gem5-users <gem5-users@gem5.org> wrote: > I forgot to mention that you have to use MESI two level of Ruby, if you want > to follow my suggestion. > > Thanks, > Jae-Eon > > 2014-09-18 14:33 GMT+09:00 Jae-Eon Jo <miruj...@gmail.com>: > Okay. > > If I understood your plan exactly, I have an idea to implement this easily. > As the implementation of CPU is decoupled from that of the memory system, you > will basically build 16-core system, but with the modification of port > assignment. > > I'll just give an illustrative example of how it can be implemented (it will > not work if you just follow it.) > (1) Modify example/fs.py > Before: > if options.ruby: > ... > for (i, cpu) in enumerate(test_sys.cpu): > After: > if options.ruby: > ... > for (i, cpu) in enumerate(test_sys.cpu): > if i % 2 == 1: continue > Then you only make L1 caches for odd cpus. > > (2) Modify topologies/Crossbar.py (if you use Crossbar topology) > Before: > routers = [Router(router_id=i) for i in range(len(self.nodes)+1)] > After: > routers = [Router(router_id=i) for i in range(len(self.nodes)/2+1)] > So, you only have a half number of routers. > > Before: > ext_links = [ExtLink(link_id=i, ext_node=n, int_node=routers[i]) > for (i, n) in enumerate(self.nodes)] > After: > ext_links = [ExtLink(link_id=i, ext_node=n, int_node=routers[i/2]) > for (i, n) in enumerate(self.nodes)] > A pair of (odd, even) CPU is assigned to the same external port. > > You can debug port assignment by appending the code right after makeTopology > call in configs/ruby/Ruby.py > for (i, node) in enumerate(topology.nodes): > print "id:%d name:%s" %(i, node.get_name()) > > Thanks, > Jae-Eon > > 2014-09-18 11:42 GMT+09:00 Chao Zhang <zhang.c...@pku.edu.cn>: > Hi Jae-Eon, > > You are right. I have just read the protocol files and it’s definitely not > trivial to modify the protocol implementation. But actually I got blocked > when I worked with the classical memory model to implement my cache > connection design. > > I want a 2-core shared L1 and a 8-L1 shared L2, which means it will have 16 > cores in the system. I used a coherent bus to connect the 2 cores and L1 > cache, and found it can work. But when I connect the 8 L1s (which means 16 > including i and d caches) with the L2, I found the request number of snooping > and the bus traffic is not affordable. And the bus busy also leads to cpu’s > fatal error. So maybe I need a directory protocol between L1 and L2. That’s > why I want to have a try at the ruby system. > > So can I get a cache system which has a snooping protocol between the > multiple-cpu and l1 and a directory protocol between L1 and L2 in ruby > system? What’s your comment to implement my design? > > Thanks a lot for your response. > > Chao > > On Sep 18, 2014, at 9:48 AM, Jae-Eon Jo via gem5-users <gem5-users@gem5.org> > wrote: > >> Hi, Chao, >> >> As far as I know, each protocol of Ruby is tightly coupled with the memory >> hierarchy. >> That is, you should modify the protocol implementation >> (src/mem/protocol/MESI_Two_Level*) to change the memory hierarchy, which is >> not trivial. >> >> My recommendation is to use the classic memory system (the default memory >> system), which models MOESI snooping protocol. >> (I think for interconnection network, if you do not have a special purpose, >> snooping is a better choice only for two cores.) >> This system is quite flexible in terms of memory hierarchy, so you can only >> modify the configuration scripts to achieve what you want. >> >> You will mostly modify two files (Note that if you modify a file under src >> directory, you need to recompile gem5): >> configs/common/CacheConfig.py (option parsing & shared L2) >> src/cpu/BaseCPU.py (private L1's & port >> connections) >> >> The current implementation has private L1 caches and shared L2 cache. To >> make L1 cache shared, you can refer to how L2 shared cache is configured. >> >> Thanks, >> Jae-Eon >> >> >> 2014-09-17 23:45 GMT+09:00 Chao Zhang via gem5-users <gem5-users@gem5.org>: >> Hi all, >> >> I’m working on ruby memory system. And I want to share a L1 cache for 2 cpu >> in ruby cache system with MESI two level protocol. How to config it? Which >> part should I work on? Thanks! >> >> Chao. >> _______________________________________________ >> gem5-users mailing list >> gem5-users@gem5.org >> http://m5sim.org/cgi-bin/mailman/listinfo/gem5-users >> >> _______________________________________________ >> gem5-users mailing list >> gem5-users@gem5.org >> http://m5sim.org/cgi-bin/mailman/listinfo/gem5-users > > > > _______________________________________________ > gem5-users mailing list > gem5-users@gem5.org > http://m5sim.org/cgi-bin/mailman/listinfo/gem5-users
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