[ofa-general] Performance penalty of OFED 1.1 versus IBGD 1.8.2
Roland Fehrenbacher
rf at q-leap.de
Wed Feb 28 05:44:41 PST 2007
>>>>> "Pavel" == Pavel Shamis <(Pasha)" <pasha at dev.mellanox.co.il>> writes:
Pavel> Hi Roland,
>> I'm migrating from IBGD 1.8.2 (kernel 2.6.15.7) to OFED 1.1,
>> and saw some unpleasant performance drops when using OFED 1.1
>> (kernel 2.6.20.1 with included IB drivers). The main drop is in
>> throughput as measured by the OSU MPI bandwidth
>> benchmark. However, the latency for large packet sizes is also
>> worse (see results below). I tried with and without "options
>> ib_mthca msi_x=1" (using IBGD, disabling msi_x makes a
>> siginficant performance difference of approx. 10%). The IB card
>> is a Mellanox MHGS18-XT (PCIe/DDR Firmware 1.2.0) running on an
>> Opteron with nForce4 2200 Professional chipset.
>>
>> Does anybody have an explanation or even better a solution to
>> this issue?
Pavel> Please try to add follow mvapich parameter :
Pavel> VIADEV_DEFAULT_MTU=MTU2048
Thanks for the suggestion. Unfortunately, it didn't improve the simple
bandwidth results. Bi-directional bandwidth increased by 3%
though. Any more ideas?
Roland
> ------------------------------------------------------------------------
>
> IBGD
> --------
>
> # OSU MPI Bandwidth Test (Version 2.1)
> # Size Bandwidth (MB/s)
> 1 0.830306
> 2 1.642710
> 4 3.307494
> 8 6.546477
> 16 13.161954
> 32 26.395154
> 64 52.913060
> 128 101.890547
> 256 172.227478
> 512 383.296292
> 1024 611.172247
> 2048 830.147571
> 4096 1068.057366
> 8192 1221.262520
> 16384 1271.771983
> 32768 1369.702828
> 65536 1426.124683
> 131072 1453.781151
> 262144 1457.297992
> 524288 1464.625860
> 1048576 1468.953875
> 2097152 1470.614903
> 4194304 1471.607758
>
> # OSU MPI Latency Test (Version 2.1)
> # Size Latency (us)
> 0 3.03
> 1 3.03
> 2 3.04
> 4 3.03
> 8 3.03
> 16 3.04
> 32 3.11
> 64 3.23
> 128 3.49
> 256 3.83
> 512 4.88
> 1024 6.31
> 2048 8.60
> 4096 11.02
> 8192 15.78
> 16384 28.85
> 32768 39.82
> 65536 60.30
> 131072 106.65
> 262144 196.47
> 524288 374.62
> 1048576 730.79
> 2097152 1442.32
> 4194304 2864.80
>
> OFED 1.1
> ---------
>
> # OSU MPI Bandwidth Test (Version 2.2)
> # Size Bandwidth (MB/s)
> 1 0.698614
> 2 1.463192
> 4 2.941852
> 8 5.859464
> 16 11.697510
> 32 23.339031
> 64 46.403081
> 128 92.013928
> 256 182.918388
> 512 315.076923
> 1024 500.083937
> 2048 765.294564
> 4096 1003.652513
> 8192 1147.640312
> 16384 1115.803139
> 32768 1221.120298
> 65536 1282.328447
> 131072 1315.715608
> 262144 1331.456393
> 524288 1340.691793
> 1048576 1345.650404
> 2097152 1349.279211
> 4194304 1350.489883
>
> # OSU MPI Latency Test (Version 2.2)
> # Size Latency (us)
> 0 2.99
> 1 3.03
> 2 3.06
> 4 3.03
> 8 3.03
> 16 3.04
> 32 3.12
> 64 3.27
> 128 3.96
> 256 4.29
> 512 4.99
> 1024 6.53
> 2048 9.08
> 4096 11.92
> 8192 17.39
> 16384 31.05
> 32768 43.47
> 65536 67.17
> 131072 115.30
> 262144 212.33
> 524288 405.20
> 1048576 790.45
> 2097152 1558.88
> 4194304 3095.17
>
>
> ------------------------------------------------------------------------
>
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