[lustre-discuss] Lnet Self Test

[Pinkesh Valdria]

Hello All, 

 

I created a new Lustre cluster on CentOS7.6 and I am running lnet_selftest_wrapper.sh to measure throughput on the network.  The nodes are connected to each other using 25Gbps ethernet, so theoretical max is 25 Gbps * 125 = 3125 MB/s.    Using iperf3,  I get 22Gbps (2750 MB/s) between the nodes.

 

 

[root at lustre-client-2 ~]# for c in 1 2 4 8 12 16 20 24 ;  do echo $c ; ST=lst-output-$(date +%Y-%m-%d-%H:%M:%S)  CN=$c  SZ=1M  TM=30 BRW=write CKSUM=simple LFROM="10.0.3.7 at tcp1" LTO="10.0.3.6 at tcp1" /root/lnet_selftest_wrapper.sh; done ;

 

When I run lnet_selftest_wrapper.sh (from Lustre wiki) between 2 nodes,  I get a max of  2055.31  MiB/s,  Is that expected at the Lnet level?  Or can I further tune the network and OS kernel (tuning I applied are below) to get better throughput?

 

 

 

Result Snippet from lnet_selftest_wrapper.sh

 

 [LNet Rates of lfrom]

[R] Avg: 4112     RPC/s Min: 4112     RPC/s Max: 4112     RPC/s

[W] Avg: 4112     RPC/s Min: 4112     RPC/s Max: 4112     RPC/s

[LNet Bandwidth of lfrom]

[R] Avg: 0.31     MiB/s Min: 0.31     MiB/s Max: 0.31     MiB/s

[W] Avg: 2055.30  MiB/s Min: 2055.30  MiB/s Max: 2055.30  MiB/s

[LNet Rates of lto]

[R] Avg: 4136     RPC/s Min: 4136     RPC/s Max: 4136     RPC/s

[W] Avg: 4136     RPC/s Min: 4136     RPC/s Max: 4136     RPC/s

[LNet Bandwidth of lto]

[R] Avg: 2055.31  MiB/s Min: 2055.31  MiB/s Max: 2055.31  MiB/s

[W] Avg: 0.32     MiB/s Min: 0.32     MiB/s Max: 0.32     MiB/s

 

 

Tuning applied: 

Ethernet NICs: 

ip link set dev ens3 mtu 9000 

ethtool -G ens3 rx 2047 tx 2047 rx-jumbo 8191

 

 

less /etc/sysctl.conf

net.core.wmem_max=16777216

net.core.rmem_max=16777216

net.core.wmem_default=16777216

net.core.rmem_default=16777216

net.core.optmem_max=16777216

net.core.netdev_max_backlog=27000

kernel.sysrq=1

kernel.shmmax=18446744073692774399

net.core.somaxconn=8192

net.ipv4.tcp_adv_win_scale=2

net.ipv4.tcp_low_latency=1

net.ipv4.tcp_rmem = 212992 87380 16777216

net.ipv4.tcp_sack = 1

net.ipv4.tcp_timestamps = 1

net.ipv4.tcp_window_scaling = 1

net.ipv4.tcp_wmem = 212992 65536 16777216

vm.min_free_kbytes = 65536

net.ipv4.tcp_congestion_control = cubic

net.ipv4.tcp_timestamps = 0

net.ipv4.tcp_congestion_control = htcp

net.ipv4.tcp_no_metrics_save = 0

 

 

 

echo "#

# tuned configuration

#

[main]

summary=Broadly applicable tuning that provides excellent performance across a variety of common server workloads

 

[disk]

devices=!dm-*, !sda1, !sda2, !sda3

readahead=>4096

 

[cpu]

force_latency=1

governor=performance

energy_perf_bias=performance

min_perf_pct=100

[vm]

transparent_huge_pages=never

[sysctl]

kernel.sched_min_granularity_ns = 10000000

kernel.sched_wakeup_granularity_ns = 15000000

vm.dirty_ratio = 30

vm.dirty_background_ratio = 10

vm.swappiness=30

" > lustre-performance/tuned.conf

 

tuned-adm profile lustre-performance

 

 

Thanks,

Pinkesh Valdria

 

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