Hello, I have a question on the single flit packets generated when synthetic traffic simulation is used. These 1 flit packets are of type HEAD_TAIL_. According to the default settings, control message (8 bytes) occupies 1 flit and a data message (72 bytes) occupies 5 flits, where each flit is 16 bytes. My question is,
Are these 1 flit packets of type HEAD_TAIL_ control messages or are they something different? Thanks for your time. Thanks, Pavan On Mon, Sep 17, 2012 at 1:56 PM, Pavan Poluri <poluripa...@gmail.com> wrote: > Thanks Tushar. > > Thanks, > Pavan > > > On Mon, Sep 17, 2012 at 11:49 AM, Tushar Krishna <tus...@csail.mit.edu>wrote: > >> Yes all that is correct. >> >> data msg size is 72 bytes, not 80. I will correct that on the wiki. >> >> cheers, >> Tushar >> >> >> On Sep 17, 2012, at 2:05 PM, Pavan Poluri wrote: >> >> Thank you. I just to make sure that I understood it the right way. >> >> In the file network/Network.py, in the declaration of RubyNetwork class >> control message size is defined as >> >> *control_msg_size = Param.Int(8, "");* >> * >> * >> So the control message size (m_control_msg_size) is 8 bytes. >> >> According to network/Network.cc, the data message size (m_data_msg_size) >> is >> >> *m_data_msg_size = RubySystem::getBlockSizeBytes() + m_control_msg_size* >> * >> * >> From ruby/system/RubySystem.py, >> >> *block_size_bytes = Param.Int(64, "default cache block size")* >> * >> * >> Therefore, m_data_size = 64+8 = 72 bytes. >> >> Since the flit size is 16 bytes, an 8 byte control message takes 1 flit >> and 72 bytes data message takes 5 flits. >> >> Am I correct? >> >> Thanks, >> Pavan >> >> On Mon, Sep 17, 2012 at 10:04 AM, Tushar Krishna <tus...@csail.mit.edu>wrote: >> >>> Answers inline. >>> >>> On Sep 17, 2012, at 12:42 PM, Pavan Poluri wrote: >>> >>> Hello, >>> >>> I have a question on the *ni_flit_size* parameter in the file >>> garnet/BaseGarnetNetwork.py. From the documentation I understood that >>> ni_flit_size specifies the flit size in bytes. The default value is 16 >>> bytes. In the documentation, it says that this results in a control message >>> fitting in 1 flit and data message fitting in 5 flits. So this means that >>> the control message is 16 bytes and the data message is 80 bytes. The >>> following are the two questions I have: >>> >>> 1. Lets say if I change the ni_flit_size to 8 bytes, would it >>> automatically translate to a control message that fits in 2 flits and data >>> message fitting in 10 flits? >>> >>> Yes. Take a look at NetworkInterface_d.cc where number of flits are >>> calculated. >>> >>> 2. Are the sizes of control message (16 bytes) and data message (80 >>> bytes) fixed? Is it possible to modify their sizes? >>> >>> Take a look at network/Network.py/cc >>> >>> Thanks for your time. >>> >>> Thanks, >>> Pavan >>> >>> On Wed, Sep 12, 2012 at 2:54 PM, Pavan Poluri <poluripa...@gmail.com>wrote: >>> >>>> Thanks Tushar. >>>> >>>> Thanks, >>>> Pavan >>>> >>>> >>>> On Wed, Sep 12, 2012 at 12:23 PM, Tushar Krishna >>>> <tus...@csail.mit.edu>wrote: >>>> >>>>> ** >>>>> If you divide the total flits by total cycles by 16, you can see that >>>>> the injection rate is only 0.0009 flits/cycle/node. Hence your power is so >>>>> low. >>>>> The total network energy might be an alternate metric that you might >>>>> want to consider instead of power to remove cycles from the picture. >>>>> Take a look at src/mem/ruby/network/orion/NetworkPower.cc where the >>>>> energy and power calculations are done. >>>>> For a relative comparison, the numbers from Orion might work for you... >>>>> You could compare the energy numbers for each component from Orion and >>>>> DSENT if you want to see how much they differ. >>>>> >>>>> The cache sizes are in configs/common/Options.py >>>>> >>>>> >>>>> On 09/12/2012 03:26 PM, Pavan Poluri wrote: >>>>> >>>>> Hi Tushar, >>>>> >>>>> The simulation ran for 5,400,912,679 cycles. How do I reduce the cache >>>>> sizes? Which source files do I need to modify? >>>>> >>>>> I was also looking into DSENT tool. To the extent I understood, the >>>>> current version of DSENT does not model the power of the Virtual Channel >>>>> Allocation stage. It only models the power for buffer, crossbar, switch >>>>> allocator and clock. I really need to calculate the power of the Virtual >>>>> Channel Allocation stage. >>>>> >>>>> Thanks for your help. >>>>> >>>>> Thanks, >>>>> Pavan >>>>> >>>>> On Wed, Sep 12, 2012 at 10:51 AM, Tushar Krishna <tus...@csail.mit.edu >>>>> > wrote: >>>>> >>>>>> Hi Pavan, >>>>>> There are two issues here. >>>>>> One, as Mitch pointed out, is that Orion is not entirely accurate. >>>>>> I would suggest computing activity counts from garnet and feeding >>>>>> them to DSENT. >>>>>> >>>>>> However, I have a feeling you will see a similar phenomenon >>>>>> (dynamic power >> leakage power) even with DSENT. >>>>>> How many cycles did your simulation run for? >>>>>> For full system runs in gem5, the network activity is typically very >>>>>> low (since network gets flits only on cache misses). >>>>>> As a result your dynamic power is very low. >>>>>> Network activity can be increased by reducing cache sizes. >>>>>> >>>>>> cheers, >>>>>> Tushar >>>>>> >>>>>> >>>>>> On Sep 12, 2012, at 1:43 PM, Pavan Poluri wrote: >>>>>> >>>>>> Hi, >>>>>> >>>>>> Thanks a lot for your detailed reply. >>>>>> >>>>>> Thanks, >>>>>> Pavan >>>>>> >>>>>> On Wed, Sep 12, 2012 at 10:32 AM, Mitch Hayenga < >>>>>> mitch.hayenga+g...@gmail.com> wrote: >>>>>> >>>>>>> Hi, >>>>>>> >>>>>>> I wouldn't trust the power model. Garnet is based on Orion, which >>>>>>> in the last year a few papers have shown to be quite inaccurate (mostly >>>>>>> because its internal model doesn't scale some technology parameters >>>>>>> properly). >>>>>>> >>>>>>> More Information: >>>>>>> 1. Peh's group recently announced a more accurate power modeling >>>>>>> tool called DSENT (https://sites.google.com/site/mitdsent/). In >>>>>>> their paper they highlight many issues with Orion and (at the 45nm node) >>>>>>> find it capable of being off by ~10x in power. >>>>>>> >>>>>>> 2. I published a WDDD paper on Orion showing my own brief >>>>>>> investigation into why its power/area numbers seemed disconnected with >>>>>>> reality. ( >>>>>>> http://www.ece.wisc.edu/~hayenga/papers/wddd2012_hayenga.pdf) >>>>>>> >>>>>>> Hope this helps. Maybe the version of Orion integrated with >>>>>>> Ruby/gem5 has received some updates, but unless you've heard otherwise, >>>>>>> I >>>>>>> wouldn't trust it. >>>>>>> >>>>>>> >>>>>>> On Wed, Sep 12, 2012 at 12:30 PM, Mitch Hayenga < >>>>>>> mitch.haye...@gmail.com> wrote: >>>>>>> >>>>>>>> Hi, >>>>>>>> >>>>>>>> I wouldn't trust the power model. Garnet is based on Orion, >>>>>>>> which in the last year a few papers have shown to be quite inaccurate >>>>>>>> (mostly because its internal model doesn't scale some technology >>>>>>>> parameters >>>>>>>> properly). >>>>>>>> >>>>>>>> More Information: >>>>>>>> 1. Peh's group recently announced a more accurate power modeling >>>>>>>> tool called DSENT (https://sites.google.com/site/mitdsent/). In >>>>>>>> their paper they highlight many issues with Orion and (at the 45nm >>>>>>>> node) >>>>>>>> find it capable of being off by ~10x in power. >>>>>>>> >>>>>>>> 2. I published a WDDD paper on Orion showing my own brief >>>>>>>> investigation into why its power/area numbers seemed disconnected with >>>>>>>> reality. ( >>>>>>>> http://www.ece.wisc.edu/~hayenga/papers/wddd2012_hayenga.pdf) >>>>>>>> >>>>>>>> Hope this helps. Maybe the version of Orion integrated with >>>>>>>> Ruby/gem5 has received some updates, but unless you've heard >>>>>>>> otherwise, I >>>>>>>> wouldn't trust it. >>>>>>>> >>>>>>>> >>>>>>>> On Wed, Sep 12, 2012 at 12:07 PM, Pavan Poluri < >>>>>>>> poluripa...@gmail.com> wrote: >>>>>>>> >>>>>>>>> Hello, >>>>>>>>> >>>>>>>>> I have executed the Blackscholes application of the PARSEC >>>>>>>>> benchmark suite with 16 threads on the input file set (in_4.txt) with >>>>>>>>> a >>>>>>>>> full system simulation with 16 cores, 16 L2 caches and 16 directories >>>>>>>>> on a >>>>>>>>> mesh topology with 4 rows. I have used the MOESI_CMP_directory >>>>>>>>> protocol. >>>>>>>>> The technology used is 90nm with a clock frequency of 1GHz and >>>>>>>>> operating >>>>>>>>> voltage VDD of 1.2V. I was going through the power statistics in the >>>>>>>>> ruby.stats file. The following are the power numbers from the >>>>>>>>> simulation. >>>>>>>>> >>>>>>>>> Router Dynamic Power = 0.00710691 W => 0.4441 mW per router >>>>>>>>> Router Static Power = 0.452366 W => 28.272 mW per router >>>>>>>>> Router Clock Power = 0.541901 W >>>>>>>>> >>>>>>>>> I am confused with these power numbers. The dynamic power is >>>>>>>>> very very less compared to the static power. I do not understand why >>>>>>>>> the >>>>>>>>> dynamic power is so low even when the simulation resulted in the >>>>>>>>> injection >>>>>>>>> of 75,899,868 flits and the successful reception of 75,899,865 flits. >>>>>>>>> Am I >>>>>>>>> doing something wrong with the simulation? Do I need to set some >>>>>>>>> parameters >>>>>>>>> for the power calculations? >>>>>>>>> >>>>>>>>> Thanks for your time. >>>>>>>>> >>>>>>>>> Thanks, >>>>>>>>> Pavan >>>>>>>>> >>>>>>>>> _______________________________________________ >>>>>>>>> gem5-users mailing list >>>>>>>>> gem5-users@gem5.org >>>>>>>>> http://m5sim.org/cgi-bin/mailman/listinfo/gem5-users >>>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> -- >>>>>>>> Mitch Hayenga >>>>>>>> mitch.haye...@gmail.com >>>>>>>> >>>>>>> >>>>>>> >>>>>>> _______________________________________________ >>>>>>> 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 >>>>>> >>>>> >>>>> >>>>> _______________________________________________ >>>>> gem5-users mailing >>>>> listgem5-users@gem5.orghttp://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 >>> >>> >>> >>> _______________________________________________ >>> 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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