Yes HEAD_TAIL_ is equivalent to HEAD_ without BODY and TAIL flits. So a single control packet is like a path guider to a single data packet? Every time a router injects a data packet into the network, it injects a control packet to initiate the data packet injection?
Thanks, Pavan On Mon, Oct 1, 2012 at 11:04 AM, Tushar Krishna <tus...@csail.mit.edu>wrote: > Why not? > HEAD_TAIL_ is equivalent to a HEAD_ right (it just so happens that there > are no BODY and TAIL flits in this packet). It still needs to choose a > route, reserve a VC (a 1-flit-deep VC in this case). > > - Tushar > > > On Oct 1, 2012, at 1:58 PM, Pavan Poluri wrote: > > Hello, > > Thanks for your reply. If the 1-flit packets of type HEAD_TAIL_ are > control messages, I am unable to figure out why do we need to perform > Routing Computation, Virtual Channel allocation etc computations on these > HEAD_TAIL_ flits? > > Thanks for your time. > > Thanks, > Pavan > > On Tue, Sep 25, 2012 at 9:53 PM, Tushar Krishna <tus...@csail.mit.edu>wrote: > >> Yes 1-flit packets (of type HEAD_TAIL_) are control messages from the >> protocol. >> >> - Tushar >> >> On Sep 25, 2012, at 8:04 PM, Pavan Poluri wrote: >> >> 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 >>>> >>> >>> >> _______________________________________________ >> 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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