[mvapich-discuss] MVAPICH2-GDR latency test return bad result

[makai]

I’m sorry, but khaled hamidouche had gave me some suggestion for my first two questions as the following:

Regarding the performance behavior, it might be because the QPI bottleneck as your GPU and HCA are in different socket. Can you please provide the details about your node configuration ?  and in meantime can you please try to explicitly select the HCA and GPU on the same socket and try? you can use the runtime parameter MV2_IBA_HCA. 

After that, I provided my IB device information to him and ask the last two questions, but I have not gotten his reply.
I’m thinking that if my questions are not quite proper and could not be understood easily.


> 在 2015年7月22日，下午11:19，Panda, Dhabaleswar <panda at cse.ohio-state.edu> 写道：
> 
> One of the MVAPICH team members had already corresponded with you on this issue a few
> weeks back outside of this list. Please follow those instructions.
> 
> Thanks,
> 
> DK
> ________________________________
> From: mvapich-discuss-bounces at cse.ohio-state.edu on behalf of makai [makailove123 at 163.com]
> Sent: Tuesday, July 21, 2015 11:50 PM
> To: mvapich-discuss at cse.ohio-state.edu
> Subject: [mvapich-discuss] MVAPICH2-GDR latency test return bad result
> 
> I have installed MVAPICH2-GDR and gdrcopy, but when I run the osu_latency, it turned out to be weird.
> 
> 
> 
> makai at gpu-cluster-3:~$ $MV2_PATH/bin/mpiexec -hosts 192.168.2.3,192.168.2.4 -n 2 -env MV2_USE_CUDA 1 /opt/mvapich2/gdr/2.1/cuda6.5/gnu/libexec/mvapich2/osu_latency D D
> # OSU MPI-CUDA Latency Test
> # Send Buffer on DEVICE (D) and Receive Buffer on DEVICE (D)
> # Size            Latency (us)
> Warning *** The GPU and IB selected are not on the same socket. Do not delever the best performance
> Warning *** The GPU and IB selected are not on the same socket. Do not delever the best performance
> 0                         1.67
> 1                         2.91
> 2                         3.92
> 4                         3.99
> 8                         3.92
> 16                        3.97
> 32                      160.67
> 64                      161.51
> 128                     162.05
> 256                     165.20
> 512                     165.88
> 1024                    168.92
> 2048                    176.08
> 4096                    185.95
> 8192                     72.63
> 16384                   261.26
> 32768                   148.08
> 65536                   518.37
> 131072                  143.93
> 262144                  260.03
> 524288                  254.41
> 1048576                 393.54
> 2097152                 672.47
> 4194304                1244.69
> 
> Why the result became so bad after size became larger than 32?
> And I find there is only one CA on my node, why it told me “The GPU and IB selected are not on the same socket. Do not delever the best performance “?
> 
> The blow is my IB information.
> 
> root at gpu-cluster-4:/mnt/docs/readme_and_user_manual# ibstat
> CA 'mlx4_0'
> CA type: MT4099
> Number of ports: 2
> Firmware version: 2.11.500
> Hardware version: 0
> Node GUID: 0x00e08100002ae95b
> System image GUID: 0x00e08100002ae95e
> Port 1:
> State: Active
> Physical state: LinkUp
> Rate: 40
> Base lid: 7
> LMC: 0
> SM lid: 1
> Capability mask: 0x02514868
> Port GUID: 0x00e08100002ae95c
> Link layer: InfiniBand
> Port 2:
> State: Active
> Physical state: LinkUp
> Rate: 40
> Base lid: 8
> LMC: 0
> SM lid: 1
> Capability mask: 0x02514868
> Port GUID: 0x00e08100002ae95d
> Link layer: InfiniBand
> 
> makai at gpu-cluster-4:~$ ibv_devinfo
> hca_id: mlx4_0
> transport: InfiniBand (0)
> fw_ver: 2.11.500
> node_guid: 00e0:8100:002a:e95b
> sys_image_guid: 00e0:8100:002a:e95e
> vendor_id: 0x02c9
> vendor_part_id: 4099
> hw_ver: 0x0
> board_id: MITAC_QDR
> phys_port_cnt: 2
> port: 1
> state: PORT_ACTIVE (4)
> max_mtu: 4096 (5)
> active_mtu: 4096 (5)
> sm_lid: 1
> port_lid: 7
> port_lmc: 0x00
> link_layer: InfiniBand
> 
> port: 2
> state: PORT_ACTIVE (4)
> max_mtu: 4096 (5)
> active_mtu: 4096 (5)
> sm_lid: 1
> port_lid: 8
> port_lmc: 0x00
> link_layer: InfiniBand
> 
> I’m not quiet understand the sockets which the GPU and the HCA belong to. How could I know whether the GPU and the HCA are belonging to the same socket?
> According to the IB device Information, there only one HCA on my node. If the GPU and the HCA belong to different sockets, could I do some configuration to their sockets?
> I have use the runtime parameter MV2_IBA_HCA=mlx4_0, but the result did not become better.
> 
> Could you give me some help?
> Thanks!
> [attachment]
> 
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