route命令参数详细说明及常用命令
原文地址 docs.lvrui.io
> route
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
default localhost 0.0.0.0 UG 100 0 0 eno16780032
172.17.0.0 0.0.0.0 255.255.0.0 U 0 0 0 docker0
192.168.10.0 0.0.0.0 255.255.255.0 U 100 0 0 eno16780032
macOS 中使用 netstat -nr 命令来查看当前路由表
简单的讲讲nginx+php的一些常用优化，以及相关的内核参数优化。
UNIX 域套接字提供的性能略高于 TCP 套接字在回送接口上的性能（较少的数据复制，较少的上下文切换）。如果每个服务器需要支持超过 1000 个连接，请使用 TCP 套接字 - 它们可以更好地扩展。
...修改supervisord配置突破1024最大连接数
最近在使用supervisord服务时发现，无论如何修改系统的最大连接数，由supervisord管理的程序都无法突破1024的限制。
...Too many open files、获取不到$HOME等
vim /etc/supervisord.conf
[supervisord]
minfds=81920
minprocs=81920
# systemctl restart supervisord
[program:apache2]
command=/home/chrism/bin/httpd -c "ErrorLog /dev/stdout" -DFOREGROUND
user=chrism
environment=HOME="/home/chrism",USER="chrism"
supervisorctl update
使用deviceQuery获取显卡信息
Linux、nvidia、cuda
/usr/local/cuda/extras/demo_suite/deviceQuery
CUDA Device Query (Runtime API) version (CUDART static linking)
Detected 2 CUDA Capable device(s)
Device 0: "GeForce RTX 2080 Ti"
CUDA Driver Version / Runtime Version 10.1 / 10.1
CUDA Capability Major/Minor version number: 7.5
Total amount of global memory: 11019 MBytes (11554717696 bytes)
(68) Multiprocessors, ( 64) CUDA Cores/MP: 4352 CUDA Cores
GPU Max Clock rate: 1545 MHz (1.54 GHz)
Memory Clock rate: 7000 Mhz
Memory Bus Width: 352-bit
L2 Cache Size: 5767168 bytes
Maximum Texture Dimension Size (x,y,z) 1D=(131072), 2D=(131072, 65536), 3D=(16384, 16384, 16384)
Maximum Layered 1D Texture Size, (num) layers 1D=(32768), 2048 layers
Maximum Layered 2D Texture Size, (num) layers 2D=(32768, 32768), 2048 layers
Total amount of constant memory: 65536 bytes
Total amount of shared memory per block: 49152 bytes
Total number of registers available per block: 65536
Warp size: 32
Maximum number of threads per multiprocessor: 1024
Maximum number of threads per block: 1024
Max dimension size of a thread block (x,y,z): (1024, 1024, 64)
Max dimension size of a grid size (x,y,z): (2147483647, 65535, 65535)
Maximum memory pitch: 2147483647 bytes
Texture alignment: 512 bytes
Concurrent copy and kernel execution: Yes with 3 copy engine(s)
Run time limit on kernels: No
Integrated GPU sharing Host Memory: No
Support host page-locked memory mapping: Yes
Alignment requirement for Surfaces: Yes
Device has ECC support: Disabled
Device supports Unified Addressing (UVA): Yes
Device supports Compute Preemption: Yes
Supports Cooperative Kernel Launch: Yes
Supports MultiDevice Co-op Kernel Launch: Yes
Device PCI Domain ID / Bus ID / location ID: 0 / 1 / 0
Compute Mode:
< Default (multiple host threads can use ::cudaSetDevice() with device simultaneously) >
Device 1: "GeForce RTX 2080 Ti"
CUDA Driver Version / Runtime Version 10.1 / 10.1
CUDA Capability Major/Minor version number: 7.5
Total amount of global memory: 11019 MBytes (11554717696 bytes)
(68) Multiprocessors, ( 64) CUDA Cores/MP: 4352 CUDA Cores
GPU Max Clock rate: 1545 MHz (1.54 GHz)
Memory Clock rate: 7000 Mhz
Memory Bus Width: 352-bit
L2 Cache Size: 5767168 bytes
Maximum Texture Dimension Size (x,y,z) 1D=(131072), 2D=(131072, 65536), 3D=(16384, 16384, 16384)
Maximum Layered 1D Texture Size, (num) layers 1D=(32768), 2048 layers
Maximum Layered 2D Texture Size, (num) layers 2D=(32768, 32768), 2048 layers
Total amount of constant memory: 65536 bytes
Total amount of shared memory per block: 49152 bytes
Total number of registers available per block: 65536
Warp size: 32
Maximum number of threads per multiprocessor: 1024
Maximum number of threads per block: 1024
Max dimension size of a thread block (x,y,z): (1024, 1024, 64)
Max dimension size of a grid size (x,y,z): (2147483647, 65535, 65535)
Maximum memory pitch: 2147483647 bytes
Texture alignment: 512 bytes
Concurrent copy and kernel execution: Yes with 3 copy engine(s)
Run time limit on kernels: No
Integrated GPU sharing Host Memory: No
Support host page-locked memory mapping: Yes
Alignment requirement for Surfaces: Yes
Device has ECC support: Disabled
Device supports Unified Addressing (UVA): Yes
Device supports Compute Preemption: Yes
Supports Cooperative Kernel Launch: Yes
Supports MultiDevice Co-op Kernel Launch: Yes
Device PCI Domain ID / Bus ID / location ID: 0 / 2 / 0
Compute Mode:
< Default (multiple host threads can use ::cudaSetDevice() with device simultaneously) >
> Peer access from GeForce RTX 2080 Ti (GPU0) -> GeForce RTX 2080 Ti (GPU1) : Yes
> Peer access from GeForce RTX 2080 Ti (GPU1) -> GeForce RTX 2080 Ti (GPU0) : Yes
deviceQuery, CUDA Driver = CUDART, CUDA Driver Version = 10.1, CUDA Runtime Version = 10.1, NumDevs = 2
https://github.com/NVIDIA/cuda-samples/tree/master/Samples/deviceQuery
...因为需要mediainfo支持http协议，在老的版本中是不支持的，所以只能自己动手编译了。
系统：ubuntu 14.04 (其他版本可能会有少许改动)
...使用openssl生产自签名证书，用于https测试。
#1.生成根证书密钥
$ openssl genrsa -out ca.key 4096 #建议长度为4096,1024长度已经被列为不安全。
#2.生成自签名根证书
$ openssl req -new -x509 -days 3650 -key ca.key -out ca.crt #这里在输入CommonName的时候输入名称而不是域名或者ip,就是证书上显示的颁发者，虽然是自签名证书，但是尽量让证书看起来标准一些
$ openssl genrsa -out server.key 4096
高版本的Chrome浏览器会要求设置 subjectAltName,如果没有设置SAN会报证书错误
Supervisor是用Python开发的一套通用的进程管理程序，能将一个普通的命令行进程变为后台daemon，并监控进程状态，异常退出时能自动重启。
...
不小心误删libc.so的恢复方式
安装完成后, 建立软链指向glibc-2.14, 执行如下命令:
rm -rf /lib64/libc.so.6
ln -s /opt/glibc-2.14/lib/libc-2.14.so /lib64/libc.so.6
注意：删除libc.so.6之后可能导致系统命令不可用的情况, 可使用如下方法解决:
...yum无法使用带https的源
yum install epel-release
运行以上命令之后，安装其他软件就报错。
[Errno 14] problem making ssl connection Trying other mirror.
Trying other mirror
Error: Cannot retrieve repository metadata (repomd.xml) for repository: xxxx. Please verify its path and try again
经过google查询，发现似乎是ssl证书的原因。
...