Hi Nikos,
I have tried to add the support for multiple DMA controllers to MESI Two
Level by using the Machine ID of the DMA controllers. The Node ID in
machine ID is the version of the machine. As per config.ini i get three
different DMA controllers with versions 0 1 2. Now the Node ID is based
upon the m_version of the controllers. I am using this Node ID to route the
request to the particular DMA controller. What I am doing is that I
broadcast response from Directory controller to all DMA controllers. Then
at DMA controller in the inport (dmaResponseQueue_in) I match the Node ID
of the controller with the Node ID of the response (the Node ID in the
response is the same as the one in the request). If a match is found then
an event of DATA or ACK is generated otherwise not.
But still I get an invalid transition (The ACK gets delivered to the wrong
DMA controller).
I want to ask that Node ID is based upon the version of the controllers and
is unique for all controllers right? If so then why the ACK still gets
delivered to wrong DMA.

What I assume is that Node ID is unique for all DMA controllers and is
based upon m_version (version in config.ini). Now the version is different
for all three controllers. If this assumption is correct then Node IDs
should be (0 1 2). Which will not result in any overlap or wrong
transition. Any suggestions? Any one?

Another thought is that I can add address ranges to DMA Controller is this
possible?
best regards,
Muhammad




On 12 June 2017 at 13:10, Nikos Nikoleris <[email protected]> wrote:

> Hi Muhammad,
>
>
> If I remember correctly, MESI_Two_Level lacks support for multiple DMA
> controllers. The request message does not store the source of the packet
> and the response doesn't reach the right DMA controller. If you have a look
> at MOESI_CMP_directory, the DMA controller (MOESI_CMP_directory-dma.sm)
> encodes the source node in the Requestor and RequestorMachine fields which
> are then used to route the response. It shouldn't be too hard to add
> something similar for the MESI_Two_Level protocol.
>
>
> Nikos
> ------------------------------
> *From:* gem5-users <[email protected]> on behalf of SHARJEEL
> KHILJI <[email protected]>
> *Sent:* 12 June 2017 07:56:51
> *To:* gem5 users mailing list
> *Subject:* [gem5-users] Invalid transition DMA controller in NoC
>
> Hi,
>
> I am running the following system,
>
> scons build/ARM/gem5.debug PROTOCOL=MESI_Two_Level
>
> ./build/ARM/gem5.debug --debug-flags ProtocolTrace  configs/example/fs.py
> --l1d_size=32kB --l1i_size=32kB --num-l2caches 4  --l2_size=1MB
> --cacheline_size=64 --machine-type=VExpress_GEM5_V1 --kernel
> /home/khilji/gem5/m5/system/binaries/vmlinux-aarch32 --disk-image
> /home/khilji/gem5/m5/system/disks/arm-ubuntu-natty-headless.img
> --dtb-filename /home/khilji/gem5/m5/system/dtb/armv7_gem5_v1_4cpu.dtb
> --num-cpus=4  --ruby --num-dirs=4 --network=garnet2.0 --topology Mesh_XY
> --mesh-rows 2 --mem-size 1GB  --cpu-clock 1GHz
>
> While running this in debug, and booting the linux I get the following
> invalid DMA transition.
> When DMA controller receives the read request from the DMA sequencer it
> moves to the busy read state
> but when input response (Data) is received from (Directory/or PUTX L1) the
> DMA has already returned to
> ready state before Data event occurs. There are three DMA controllers
> (equal to dma ports) in the system as specified in config.ini.
> Is this because of the fact that one of the controllers issues the read
> request to directory and all of the controllers receive the response?
> and then those who have not issued the request receive the response while
> in ready state which results in exception.
> Following is the protocol trace
>
>    646885666000   2    L1Cache             Load
> M>M                        [0xbda99a00, line 0xbda99a00]
>    646885667000   2        Seq               Begin
> >                            [0x80359d7c, line 0x80359d40] IFETCH
>    646885668000   2        Seq                Done
> >                            [0x80359d7c, line 0x80359d40] 1 cycles
>    646885668000   2    L1Cache              Ifetch
> S>S                       [0x80359d40, line 0x80359d40]
>    646885670500   1        DMA         ReadRequest
> READY>BUSY_RD                 [0xbf040000, line 0xbf040000]
>    646885676000   0  Directory            DMA_READ   M>M_DRD
> [0xbf040000, line 0xbf040000]
>    646885681500   0    L2Cache             MEM_Inv    MT>MT_I
> [0xbf040000, line 0xbf040000]
>    646885681500   0    L2Cache             MEM_Inv    MT_I>MT_I
> [0xbf040000, line 0xbf040000]
>    646885685500   2    L1Cache                 Inv
> M>I                         [0xbf040000, line 0xbf040000]
>    646885694000   0    L2Cache             WB_Data    MT_I>M_I
> [0xbf040000, line 0xbf040000]
>    646885700000   0  Directory                Data
> M_DRD>M_DRDI          [0xbf040000, line 0xbf040000]
>
> panic: Invalid transition
> system.ruby.dma_cntrl0 time: 1293771411 addr: 3204710400 event: Data
> state: READY
> Memory Usage: 1584496 KBytes
> Program aborted at tick 646885705500
>
> Any suggestions?
>
> best regards,
> Muhammad
>
>
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