Question about ImageNet with multi T4

username: sakaia
cooked: <p>I try to run the single node with multi gpu (T4) on AWS g4dn.12xlarge of<br>
examples/imagenet. (Options are taken by README.md with --epochs 1)</p>
<p><code>python main.py -a resnet50 --dist-url 'tcp://127.0.0.1:6007' --epochs 1 --dist-backend 'nccl' --multiprocessing-distributed --world-size 1 --rank 0 ~/imagenette-320</code></p>
<p>I get following output log (with NCCL_DEBUG=INFO)<br>
I suspect 4 GPU works do the same operation.(not data parallel)<br>
Is my understanding incorrect?<br>
If this should goes to issue tracker, I will write it on examples issue.</p>
<p>P.S.<br>
I try to upload log file separately but it is not available.<br>
So I paste the log.</p>
<p>===<br>
ip-172-31-35-240:19495:19495 [0] NCCL INFO Bootstrap : Using [0]ens5:172.31.35.240&lt;0&gt;</p>
<p>ip-172-31-35-240:19495:19495 [0] ofi_init:700 NCCL WARN NET/OFI Only EFA provider is supported<br>
ip-172-31-35-240:19495:19495 [0] NCCL INFO NET/IB : No device found.<br>
ip-172-31-35-240:19495:19495 [0] NCCL INFO NET/Socket : Using [0]ens5:172.31.35.240&lt;0&gt;<br>
NCCL version 2.4.8+cuda10.1<br>
ip-172-31-35-240:19497:19497 [2] NCCL INFO Bootstrap : Using [0]ens5:172.31.35.240&lt;0&gt;<br>
ip-172-31-35-240:19496:19496 [1] NCCL INFO Bootstrap : Using [0]ens5:172.31.35.240&lt;0&gt;<br>
ip-172-31-35-240:19498:19498 [3] NCCL INFO Bootstrap : Using [0]ens5:172.31.35.240&lt;0&gt;</p>
<p>ip-172-31-35-240:19498:19498 [3] ofi_init:700 NCCL WARN NET/OFI Only EFA provider is supported</p>
<p>ip-172-31-35-240:19497:19497 [2] ofi_init:700 NCCL WARN NET/OFI Only EFA provider is supported</p>
<p>ip-172-31-35-240:19496:19496 [1] ofi_init:700 NCCL WARN NET/OFI Only EFA provider is supported<br>
ip-172-31-35-240:19497:19497 [2] NCCL INFO NET/IB : No device found.<br>
ip-172-31-35-240:19496:19496 [1] NCCL INFO NET/IB : No device found.<br>
ip-172-31-35-240:19498:19498 [3] NCCL INFO NET/IB : No device found.<br>
ip-172-31-35-240:19497:19497 [2] NCCL INFO NET/Socket : Using [0]ens5:172.31.35.240&lt;0&gt;<br>
ip-172-31-35-240:19496:19496 [1] NCCL INFO NET/Socket : Using [0]ens5:172.31.35.240&lt;0&gt;<br>
ip-172-31-35-240:19498:19498 [3] NCCL INFO NET/Socket : Using [0]ens5:172.31.35.240&lt;0&gt;<br>
ip-172-31-35-240:19495:19521 [0] NCCL INFO Setting affinity for GPU 0 to ffff,ffffffff<br>
ip-172-31-35-240:19497:19522 [2] NCCL INFO Setting affinity for GPU 2 to ffff,ffffffff<br>
ip-172-31-35-240:19496:19523 [1] NCCL INFO Setting affinity for GPU 1 to ffff,ffffffff<br>
ip-172-31-35-240:19498:19524 [3] NCCL INFO Setting affinity for GPU 3 to ffff,ffffffff<br>
ip-172-31-35-240:19495:19521 [0] NCCL INFO Channel 00 :    0   1   2   3<br>
ip-172-31-35-240:19498:19524 [3] NCCL INFO Ring 00 : 3[3] -&gt; 0[0] via direct shared memory<br>
ip-172-31-35-240:19496:19523 [1] NCCL INFO Ring 00 : 1[1] -&gt; 2[2] via direct shared memory<br>
ip-172-31-35-240:19497:19522 [2] NCCL INFO Ring 00 : 2[2] -&gt; 3[3] via direct shared memory<br>
ip-172-31-35-240:19495:19521 [0] NCCL INFO Ring 00 : 0[0] -&gt; 1[1] via direct shared memory<br>
ip-172-31-35-240:19495:19521 [0] NCCL INFO Using 256 threads, Min Comp Cap 7, Trees disabled<br>
ip-172-31-35-240:19496:19523 [1] NCCL INFO comm 0x7efc6c001b60 rank 1 nranks 4 cudaDev 1 nvmlDev 1 - Init COMPLETE<br>
ip-172-31-35-240:19498:19524 [3] NCCL INFO comm 0x7f536c001b60 rank 3 nranks 4 cudaDev 3 nvmlDev 3 - Init COMPLETE<br>
ip-172-31-35-240:19497:19522 [2] NCCL INFO comm 0x7fda80001b60 rank 2 nranks 4 cudaDev 2 nvmlDev 2 - Init COMPLETE<br>
ip-172-31-35-240:19495:19521 [0] NCCL INFO comm 0x7fce48001b60 rank 0 nranks 4 cudaDev 0 nvmlDev 0 - Init COMPLETE<br>
ip-172-31-35-240:19495:19495 [0] NCCL INFO Launch mode Parallel<br>
Use GPU: 1 for training<br>
=&gt; creating model ‘resnet50’<br>
Use GPU: 2 for training<br>
=&gt; creating model ‘resnet50’<br>
Use GPU: 0 for training<br>
=&gt; creating model ‘resnet50’<br>
Use GPU: 3 for training<br>
=&gt; creating model ‘resnet50’<br>
Epoch: [0][ 0/51]	Time  4.175 ( 4.175)	Data  0.817 ( 0.817)	Loss 7.1020e+00 (7.1020e+00)	Acc@1   0.00 (  0.00)	Acc@5   0.00 (  0.00)<br>
Epoch: [0][10/51]	Time  0.568 ( 0.884)	Data  0.000 ( 0.075)	Loss 6.2389e+00 (2.7609e+01)	Acc@1  12.50 ( 10.37)	Acc@5  51.56 ( 50.28)<br>
Epoch: [0][20/51]	Time  0.573 ( 0.735)	Data  0.000 ( 0.047)	Loss 4.8649e+00 (1.9667e+01)	Acc@1  12.50 ( 10.04)	Acc@5  64.06 ( 49.93)<br>
Epoch: [0][30/51]	Time  0.576 ( 0.682)	Data  0.000 ( 0.037)	Loss 2.6044e+00 (1.4510e+01)	Acc@1   9.38 ( 10.08)	Acc@5  51.56 ( 50.30)<br>
Epoch: [0][40/51]	Time  0.578 ( 0.656)	Data  0.000 ( 0.032)	Loss 2.3226e+00 (1.1761e+01)	Acc@1   7.81 ( 10.18)	Acc@5  57.81 ( 49.85)<br>
Epoch: [0][50/51]	Time  1.896 ( 0.666)	Data  0.000 ( 0.029)	Loss 2.3349e+00 (1.0023e+01)	Acc@1   8.33 ( 10.14)	Acc@5  50.00 ( 50.00)<br>
Epoch: [0][ 0/51]	Time  4.166 ( 4.166)	Data  0.808 ( 0.808)	Loss 7.1076e+00 (7.1076e+00)	Acc@1   0.00 (  0.00)	Acc@5   0.00 (  0.00)<br>
Epoch: [0][10/51]	Time  0.569 ( 0.886)	Data  0.000 ( 0.076)	Loss 9.1219e+00 (1.8244e+01)	Acc@1   9.38 (  9.09)	Acc@5  48.44 ( 46.02)<br>
Epoch: [0][20/51]	Time  0.573 ( 0.736)	Data  0.000 ( 0.047)	Loss 4.3179e+00 (1.2560e+01)	Acc@1  12.50 (  9.52)	Acc@5  45.31 ( 47.77)<br>
Epoch: [0][30/51]	Time  0.575 ( 0.683)	Data  0.000 ( 0.037)	Loss 2.7694e+00 (9.7450e+00)	Acc@1  17.19 ( 10.13)	Acc@5  59.38 ( 49.04)<br>
Epoch: [0][40/51]	Time  0.581 ( 0.657)	Data  0.000 ( 0.032)	Loss 2.2670e+00 (7.9916e+00)	Acc@1  23.44 ( 11.09)	Acc@5  62.50 ( 49.92)<br>
Epoch: [0][50/51]	Time  1.879 ( 0.666)	Data  0.000 ( 0.028)	Loss 2.2895e+00 (6.9589e+00)	Acc@1  12.50 ( 10.83)	Acc@5  41.67 ( 49.44)<br>
Epoch: [0][ 0/51]	Time  4.183 ( 4.183)	Data  0.815 ( 0.815)	Loss 7.1518e+00 (7.1518e+00)	Acc@1   0.00 (  0.00)	Acc@5   0.00 (  0.00)<br>
Epoch: [0][10/51]	Time  0.571 ( 0.885)	Data  0.000 ( 0.075)	Loss 5.8699e+00 (2.7128e+01)	Acc@1  10.94 (  9.38)	Acc@5  51.56 ( 48.15)<br>
Epoch: [0][20/51]	Time  0.571 ( 0.735)	Data  0.000 ( 0.047)	Loss 4.1080e+00 (1.7798e+01)	Acc@1   6.25 (  9.30)	Acc@5  45.31 ( 50.22)<br>
Epoch: [0][30/51]	Time  0.574 ( 0.682)	Data  0.000 ( 0.037)	Loss 3.8085e+00 (1.3301e+01)	Acc@1   7.81 (  9.68)	Acc@5  46.88 ( 50.15)<br>
Epoch: [0][40/51]	Time  0.582 ( 0.656)	Data  0.000 ( 0.032)	Loss 2.4562e+00 (1.0682e+01)	Acc@1  10.94 ( 10.25)	Acc@5  51.56 ( 50.61)<br>
Epoch: [0][50/51]	Time  1.902 ( 0.666)	Data  0.000 ( 0.029)	Loss 2.3628e+00 (9.2144e+00)	Acc@1   0.00 (  9.99)	Acc@5  45.83 ( 50.43)<br>
Epoch: [0][ 0/51]	Time  4.189 ( 4.189)	Data  0.823 ( 0.823)	Loss 7.0857e+00 (7.0857e+00)	Acc@1   0.00 (  0.00)	Acc@5   0.00 (  0.00)<br>
Epoch: [0][10/51]	Time  0.568 ( 0.885)	Data  0.000 ( 0.075)	Loss 5.9996e+00 (1.6526e+01)	Acc@1  10.94 (  9.66)	Acc@5  51.56 ( 45.03)<br>
Epoch: [0][20/51]	Time  0.570 ( 0.735)	Data  0.000 ( 0.047)	Loss 4.8403e+00 (1.1769e+01)	Acc@1  12.50 ( 10.49)	Acc@5  50.00 ( 47.54)<br>
Epoch: [0][30/51]	Time  0.569 ( 0.682)	Data  0.000 ( 0.037)	Loss 2.8636e+00 (9.2034e+00)	Acc@1   7.81 ( 10.13)	Acc@5  59.38 ( 49.90)<br>
Epoch: [0][40/51]	Time  0.572 ( 0.656)	Data  0.000 ( 0.032)	Loss 2.3001e+00 (7.5971e+00)	Acc@1   6.25 ( 10.75)	Acc@5  51.56 ( 49.54)<br>
Epoch: [0][50/51]	Time  1.898 ( 0.666)	Data  0.000 ( 0.029)	Loss 6.2036e+00 (6.7050e+00)	Acc@1   4.17 ( 10.61)	Acc@5  66.67 ( 49.81)<br>
Test: [0/8]	Time  0.997 ( 0.997)	Loss 2.5230e+00 (2.5230e+00)	Acc@1   9.38 (  9.38)	Acc@5 100.00 (100.00)</p>
<ul>
<li>Acc@1 12.400 Acc@5 54.200<br>
Test: [0/8]	Time  0.997 ( 0.997)	Loss 2.5230e+00 (2.5230e+00)	Acc@1   9.38 (  9.38)	Acc@5 100.00 (100.00)</li>
<li>Acc@1 12.400 Acc@5 54.200<br>
Test: [0/8]	Time  0.992 ( 0.992)	Loss 2.5230e+00 (2.5230e+00)	Acc@1   9.38 (  9.38)	Acc@5 100.00 (100.00)</li>
<li>Acc@1 12.400 Acc@5 54.200<br>
Test: [0/8]	Time  0.988 ( 0.988)	Loss 2.5230e+00 (2.5230e+00)	Acc@1   9.38 (  9.38)	Acc@5 100.00 (100.00)</li>
<li>Acc@1 12.400 Acc@5 54.200<br>
===</li>
</ul>