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 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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