（可选）安装knem组件

knem是MPI节点内通信的一个增强组件，在部分HPC应用中，对于MPI通信中大包场景，安装使能该组件后在时会有一些性能提升。

检查knem使能情况

安装knem组件前，可以先检查knem使能情况，如果可以使能成功则无需再安装knem。

执行命令 cat /dev/knem，回显如下表示安装正常。

knem 1.1.4.90 (git20250207.4b4ebc6)
 Driver ABI=0xd
 Flags: forcing 0x0, ignoring 0x0
 DMAEngine: NoKernelSupport
 Debug: NotBuilt
 Requests submitted                           : 16320
 Requests processed (total)                   : 16320
          processed (using DMA)               : 0
          processed (offloaded to thread)     : 0
          processed (with pinned local pages) : 0
 Requests rejected (invalid flags)            : 0
          rejected (not enough memory)        : 0
          rejected (invalid ioctl argument)   : 0
          rejected (unexisting region cookie) : 0
          rejected (failed to pin local pages): 0
 Requests failed during memcpy from/to user   : 0
          failed during DMA copy              : 0
 DMA copy cleanup timeout                     : 0

如果knem未正常使能，可以尝试安装knem后，再次使用上述方法确认使能情况。

安装knem

knem需要在每个计算节点安装。

下载rpm包（不同os对应的rpm包不同）。
- openEuler 20.03 LTS AArch64
  wget --no-check-certificate https://repo.oepkgs.net/openeuler/rpm/openEuler-20.03-LTS-SP1/extras/aarch64/Packages/k/knem-1.1.4.90-0.aarch64.rpm
- openEuler 22.03 LTS AArch64
  wget --no-check-certificate https://repo.oepkgs.net/openeuler/rpm/openEuler-22.03-LTS/extras/aarch64/Packages/k/knem-1.1.4.90-0.aarch64.rpm
- 银河麒麟高级服务器操作系统V10（HPC版） AArch64
  wget --no-check-certificate https://repo.oepkgs.net/openeuler/rpm/openEuler-22.03-LTS/extras/aarch64/Packages/k/knem-1.1.4.90-0.ky10h.aarch64.rpm
- Kylin Linux Advanced Server V10 SP2 AArch64
  wget --no-check-certificate https://repo.oepkgs.net/openeuler/rpm/openEuler-20.03-LTS-SP1/extras/aarch64/Packages/k/knem-1.1.4.90-0.ky10.aarch64.rpm
- 麒麟信安服务器操作系统V3.5.2 AArch64
  wget --no-check-certificate https://repo.oepkgs.net/openeuler/rpm/openEuler-22.03-LTS/extras/aarch64/Packages/k/knem-1.1.4.90-0.aarch64.rpm
安装rpm包。
rpm -ivh rpm包名称

如果回显提示有系统自带rpm包，新的rpm包无法被安装，则需要手动卸载系统自带rpm包，再重新安装。
检查knem内核是否加载，如果回显出现“knem”说明加载成功。
lsmod | grep knem
1
knem 57344 4

执行命令 cat /dev/knem，回显如下表示安装成功。

knem 1.1.4.90 (git20250207.4b4ebc6)
 Driver ABI=0xd
 Flags: forcing 0x0, ignoring 0x0
 DMAEngine: NoKernelSupport
 Debug: NotBuilt
 Requests submitted                           : 16320
 Requests processed (total)                   : 16320
          processed (using DMA)               : 0
          processed (offloaded to thread)     : 0
          processed (with pinned local pages) : 0
 Requests rejected (invalid flags)            : 0
          rejected (not enough memory)        : 0
          rejected (invalid ioctl argument)   : 0
          rejected (unexisting region cookie) : 0
          rejected (failed to pin local pages): 0
 Requests failed during memcpy from/to user   : 0
          failed during DMA copy              : 0
 DMA copy cleanup timeout                     : 0

执行以下命令，运行knem的自带测试用例 knem_pingpong，默认安装在/opt/knem-1.1.4.90 。

cd /path/to/install

/path/to/install/bin/knem_pingpong

/path/to/install表示knem安装目录。

1024:	  25.705 us	39.84 MB/s	 37.99 MiB/s
2048:	  25.869 us	79.17 MB/s	 75.50 MiB/s
4096:	  29.301 us	139.79 MB/s	 133.32 MiB/s
8192:	  30.902 us	265.09 MB/s	 252.81 MiB/s
16384:	  35.213 us	465.28 MB/s	 443.73 MiB/s
32768:	  45.170 us	725.44 MB/s	 691.83 MiB/s
65536:	  69.500 us	942.96 MB/s	 899.28 MiB/s
131072:	  62.795 us	2087.30 MB/s	 1990.61 MiB/s
262144:	  91.160 us	2875.64 MB/s	 2742.43 MiB/s
524288:	  158.172 us	3314.67 MB/s	 3161.12 MiB/s
1048576:  216.383 us	4845.93 MB/s	 4621.44 MiB/s
2097152:  310.549 us	6753.05 MB/s	 6440.21 MiB/s
4194304:  329.018 us	12747.96 MB/s	 12157.40 MiB/s
8388608:  615.082 us	13638.19 MB/s	 13006.40 MiB/s
16777216: 1232.287 us	13614.70 MB/s	 12983.99 MiB/s

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