关于 Linux中系统调优的一些笔记（二）（关于我转生变成史莱姆这档事）

写在前面

推送的的邮件里看到有大佬讲的公共课，听了之后这里整理学习笔记。

因为是公开课，所以讲的很浅，没接触过，这里做为了解，长长见识。

博文内容包括：

接上篇

我突然又明白，死亡是聪明的兄长，我们可以放心地把自己托付给他，他会知道在我们有所准备的适当时刻前来。我也突然懂得，原来痛苦、失望和悲愁不是为了惹恼我们，使我们气馁或者无地自容；它们的存在，是为了使我们心智成熟，臻于完善。--------—赫尔曼·黑塞《彼得·卡门青》

内核调优之清理缓存

如何使用帮助调整内核参数

┌──[root@liruilongs.github.io]-[/proc/sys/vm] └─$ man -K drop_caches --Man-- next: proc(5) [ view (return) | skip (Ctrl-D) | quit (Ctrl-C) ]

┌──[root@liruilongs.github.io]-[/proc/sys/vm] └─$ cat drop_caches #缓存处理 0 ┌──[root@liruilongs.github.io]-[/proc/sys/vm] └─$ man -K drop_caches No manual entry for drop_caches ┌──[root@liruilongs.github.io]-[/proc/sys/vm] └─$ man -K drop_caches No manual entry for drop_caches ┌──[root@liruilongs.github.io]-[/proc/sys/vm] └─$ man -K ip_forward ┌──[root@liruilongs.github.io]-[/proc/sys/vm] └─$ free -m total used free shared buff/cache available Mem: 3935 212 3357 16 366 3440 Swap: 10239 0 10239 ┌──[root@liruilongs.github.io]-[/proc/sys/vm] └─$ echo 3 > /proc/sys/vm/drop_caches ┌──[root@liruilongs.github.io]-[/proc/sys/vm] └─$ free -m total used free shared buff/cache available Mem: 3935 200 3575 16 159 3504 Swap: 10239 0 10239 ┌──[root@liruilongs.github.io]-[/proc/sys/vm] └─$

调整内核模块参数：lsmod、modinfo、modprobe

加载的内核模块列表 lsmod

┌──[root@liruilongs.github.io]-[/proc/sys/vm] └─$ lsmod # 大小 调用次数 Module Size Used by binfmt_misc 17468 1 xt_conntrack 12760 2 ipt_MASQUERADE 12678 2 nf_nat_masquerade_ipv4 13412 1 ipt_MASQUERADE nf_conntrack_netlink 40449 0 nfnetlink 14696 2 nf_conntrack_netlink xt_addrtype 12676 2 iptable_filter 12810 1 iptable_nat 12875 1 nf_conntrack_ipv4 15053 3 nf_defrag_ipv4 12729 1 nf_conntrack_ipv4 。。。。。 。。。。。。 crct10dif_common 12595 3 crct10dif_pclmul,crct10dif_generic,crc_t10dif crc32c_intel 22079 1 ahci 34042 0 drm 370825 2 ttm,drm_kms_helper libahci 31992 1 ahci mptspi 22542 2 ata_piix 35038 0 scsi_transport_spi 30732 1 mptspi mptscsih 40150 1 mptspi libata 238896 5 ahci,pata_acpi,libahci,ata_generic,ata_piix e1000 137500 0 serio_raw 13413 0 mptbase 105960 2 mptspi,mptscsih i2c_core 40756 3 drm,i2c_piix4,drm_kms_helper ┌──[root@liruilongs.github.io]-[/proc/sys/vm] └─$

查看内核模块参数 modinfo

┌──[root@liruilongs.github.io]-[/proc/sys/vm] └─$ modinfo kvm # 查看内核模块参数 filename: /lib/modules/3.10.0-693.el7.x86_64/kernel/arch/x86/kvm/kvm.ko.xz license: GPL author: Qumranet rhelversion: 7.4 srcversion: FA3AAB0FB1DD5C7B9D69811 depends: irqbypass intree: Y vermagic: 3.10.0-693.el7.x86_64 SMP mod_unload modversions signer: CentOS linux kernel signing key sig_key: DA:18:7D:CA:7D:BE:53:AB:05:BD:13:BD:0C:4E:21:F4:22:B6:A4:9C sig_hashalgo: sha256 parm: ignore_msrs:bool parm: min_timer_period_us:uint parm: kvmclock_periodic_sync:bool parm: tsc_tolerance_ppm:uint parm: lapic_timer_advance_ns:uint parm: vector_hashing:bool parm: halt_poll_ns:uint parm: halt_poll_ns_grow:uint parm: halt_poll_ns_shrink:uint ┌──[root@liruilongs.github.io]-[/proc/sys/vm] └─$

内核模块调优之嵌套虚拟化设置

┌──[root@liruilongs.github.io]-[/proc/sys/vm] └─$ modinfo kvm filename: /lib/modules/3.10.0-693.el7.x86_64/kernel/arch/x86/kvm/kvm.ko.xz license: GPL author: Qumranet rhelversion: 7.4 srcversion: FA3AAB0FB1DD5C7B9D69811 depends: irqbypass intree: Y vermagic: 3.10.0-693.el7.x86_64 SMP mod_unload modversions signer: CentOS Linux kernel signing key sig_key: DA:18:7D:CA:7D:BE:53:AB:05:BD:13:BD:0C:4E:21:F4:22:B6:A4:9C sig_hashalgo: sha256 parm: ignore_msrs:bool parm: min_timer_period_us:uint parm: kvmclock_periodic_sync:bool parm: tsc_tolerance_ppm:uint parm: lapic_timer_advance_ns:uint parm: vector_hashing:bool parm: halt_poll_ns:uint parm: halt_poll_ns_grow:uint parm: halt_poll_ns_shrink:uint ┌──[root@liruilongs.github.io]-[/proc/sys/vm] └─$ modinfo kvm | grep ignore_msrs # 设置允许嵌套虚拟化 parm: ignore_msrs:bool ┌──[root@liruilongs.github.io]-[/etc/modprobe.d] └─$ echo "options kvm ignore_msrs=1" >> /etc/modprobe.d/kvm.conf ##从起机器

如何限制服务的资源占用

资源消耗分为用户和服务，消耗：CPU，内存和 I/O

经典的限制通过 pam_limit 模块配合 /etc/security/limits.conf 实现（用户）

用户登录会加载pam_limit模块，pam_limit模块读取配置文件 /etc/security/limits.conf限制用户资源的占用

┌──[root@liruilongs.github.io]-[/etc/modprobe.d] └─$ cat /etc/security/limits.conf # /etc/security/limits.conf # #This file sets the resource limits for the users logged in via PAM. #It does not affect resource limits of the system services. # #Also note that configuration files in /etc/security/limits.d directory, #which are read in alphabetical order, override the settings in this #file in case the domain is the same or more specific. #That means for example that setting a limit for wildcard domain here #can be overriden with a wildcard setting in a config file in the #subdirectory, but a user specific setting here can be overriden only #with a user specific setting in the subdirectory. # #Each line describes a limit for a user in the form: # # # #Where: # can be: # - a user name # - a group name, with @group syntax # - the wildcard *, for default entry # - the wildcard %, can be also used with %group syntax, # for maxlogin limit # # can have the two values: # - "soft" for enforcing the soft limits # - "hard" for enforcing hard limits # # can be one of the following: # - core - limits the core file size (KB) 核心文件大小 # - data - max data size (KB) # - fsize - maximum filesize (KB) # - memlock - max locked-in-memory address space (KB) # - nofile - max number of open file descriptors # 访问文件数量 # - rss - max resident set size (KB) # - stack - max stack size (KB) # - cpu - max CPU time (MIN) # cup时间 # - nproc - max number of processes # - as - address space limit (KB) # - maxlogins - max number of logins for this user #最多的登录数 # - maxsyslogins - max number of logins on the system # - priority - the priority to run user process with # - locks - max number of file locks the user can hold # - sigpending - max number of pending signals # - msgqueue - max memory used by POSIX message queues (bytes) # - nice - max nice priority allowed to raise to values: [-20, 19] # - rtprio - max realtime priority # # # #* soft core 0 #* hard rss 10000 #@student hard nproc 20 #@faculty soft nproc 20 #@faculty hard nproc 50 #ftp hard nproc 0 #@student - maxlogins 4 # End of file

限制服务的资源之限制用户通过ssh的登录数

┌──[root@liruilongs.github.io]-[/etc/modprobe.d] └─$vim /etc/security/limits.conf student hard maxlogins 4

也可以通过 cgroup 实现资源的限制(服务)

┌──[root@liruilongs.github.io]-[/etc/modprobe.d] └─$ md5sum /dev/urandom & #启动一个进程 cpu100% [1] 38162 ┌──[root@liruilongs.github.io]-[/etc/modprobe.d] └─$ top top - 13:37:42 up 4:10, 1 user, load average: 1.03, 0.80, 0.43 Tasks: 158 total, 2 running, 156 sleeping, 0 stopped, 0 zombie %Cpu(s): 2.0 us, 53.9 sy, 0.0 ni, 43.3 id, 0.0 wa, 0.0 hi, 0.8 si, 0.0 st KiB Mem : 4030172 total, 3637840 free, 207252 used, 185080 buff/cache KiB Swap: 10485756 total, 10485756 free, 0 used. 3575580 avail Mem PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 861 etcd 20 0 10.254g 22572 11092 S 9.7 0.6 22:07.49 etcd 9 root 20 0 0 0 0 S 1.7 0.0 0:28.00 rcu_sched 595 root 20 0 298868 6260 4916 S 1.6 0.2 2:27.63 vmtoolsd 371 root 20 0 0 0 0 S 0.4 0.0 1:23.11 xfsaild/sda1 1 root 20 0 51688 3960 2624 S 0.4 0.1 0:31.08 systemd 36765 root 20 0 0 0 0 S 0.2 0.0 0:03.13 kworker/1:0 583 root 20 0 21616 1284 972 S 0.2 0.0 0:09.59 irqbalance 857 root 20 0 573468 16760 6020 S 0.2 0.4 0:14.24 tuned 13 root 20 0 0 0 0 S 0.2 0.0 0:06.16 ksoftirqd/1 864 root 20 0 1015116 42652 13740 S 0.1 1.1 0:22.33 containerd 853 root 20 0 228220 5128 3240 S 0.1 0.1 0:09.13 httpd 594 root 20 0 224504 12424 3348 S 0.1 0.3 0:08.61 rsyslogd 649 chrony 20 0 117704 1772 1312 S 0.1 0.0 0:03.47 chronyd 7604 root 20 0 151984 5352 4088 R 0.1 0.1 0:05.89 sshd 38166 root 20 0 161908 2264 1556 R 0.1 0.1 0:00.10 top 1055 root 20 0 81744 3132 2168 S 0.0 0.1 0:10.09 pmdalinux 8095 root 20 0 0 0 0 S 0.0 0.0 0:01.54 kworker/u256:0 11 root rt 0 0 0 0 S 0.0 0.0 0:02.17 watchdog/1 1051 root 20 0 81628 2700 1912 S 0.0 0.1 0:03.07 pmdaproc 2 root 20 0 0 0 0 S 0.0 0.0 0:00.09 kthreadd 3 root 20 0 0 0 0 S 0.0 0.0 0:01.56 ksoftirqd/0 5 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 kworker/0:0H 7 root rt 0 0 0 0 S 0.0 0.0 0:01.08 migration/0 [1]+ Terminated md5sum /dev/urandom ┌──[root@liruilongs.github.io]-[/etc/modprobe.d] └─$

现在我们把这个写成一个服务，然后通过cgroup做简单限制。

┌──[root@liruilongs.github.io]-[~] └─$ vim /etc/systemd/system/md5sum.service ┌──[root@liruilongs.github.io]-[~] └─$ cat /etc/systemd/system/md5sum.service [Unit] Description=MD5 Demo [Service] CPUQuota=40% ExecStart=/usr/bin/md5sum /dev/urandom [Install] WantedBy=multi-user.target ┌──[root@liruilongs.github.io]-[~] └─$ ┌──[root@liruilongs.github.io]-[~] └─$ systemctl daemon-reload ┌──[root@liruilongs.github.io]-[~] └─$ systemctl start md5sum.service ┌──[root@liruilongs.github.io]-[~] └─$ top top - 19:12:14 up 9:44, 1 user, load average: 0.29, 0.20, 0.11 Tasks: 159 total, 2 running, 157 sleeping, 0 stopped, 0 zombie %Cpu(s): 0.5 us, 20.3 sy, 0.0 ni, 78.8 id, 0.0 wa, 0.0 hi, 0.4 si, 0.0 st KiB Mem : 4030172 total, 3606960 free, 209832 used, 213380 buff/cache KiB Swap: 10485756 total, 10485756 free, 0 used. 3558764 avail Mem PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 59598 root 20 0 107920 612 516 R 39.7 0.0 0:02.54 md5sum ##CPU限制为40% 861 etcd 20 0 10.254g 22572 11092 S 6.3 0.6 51:24.88 etcd 59601 root 20 0 161908 2268 1560 R 1.0 0.1 0:00.08 top 595 root 20 0 298868 6260 4916 S 0.7 0.2 5:35.80 vmtoolsd 1 root 20 0 51688 4000 2648 S 0.3 0.1 1:15.99 systemd 9 root 20 0 0 0 0 S 0.3 0.0 0:50.90 rcu_sched 371 root 20 0 0 0 0 S 0.3 0.0 3:02.41 xfsaild/sda1 6671 root 20 0 1309148 66444 25620 S 0.3 1.6 0:48.35 dockerd 2 root 20 0 0 0 0 S 0.0 0.0 0:00.13 kthreadd 3 root 20 0 0 0 0 S 0.0 0.0 0:04.25 ksoftirqd/0 5 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 kworker/0:0H 7 root rt 0 0 0 0 S 0.0 0.0 0:02.39 migration/0 8 root 20 0 0 0 0 S 0.0 0.0 0:00.00 rcu_bh 10 root rt 0 0 0 0 S 0.0 0.0 0:03.13 watchdog/0 11 root rt 0 0 0 0 S 0.0 0.0 0:04.80 watchdog/1 12 root rt 0 0 0 0 S 0.0 0.0 0:02.72 migration/1 13 root 20 0 0 0 0 S 0.0 0.0 0:11.18 ksoftirqd/1 15 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 kworker/1:0H 17 root 20 0 0 0 0 S 0.0 0.0 0:00.11 kdevtmpfs 18 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 netns 19 root 20 0 0 0 0 S 0.0 0.0 0:00.08 khungtaskd 20 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 writeback 21 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 kintegrityd ┌──[root@liruilongs.github.io]-[~] └─$

这个具体小伙伴可以看看这篇博客: https://blog.csdn.net/sanhewuyang/article/details/120735766

关于cgroup参数设置可以使用帮助文档

┌──[root@liruilongs.github.io]-[~] └─$ man -k systemd ┌──[root@liruilongs.github.io]-[~] └─$ man systemd.resource-control ┌──[root@liruilongs.github.io]-[~] └─$

为 systemd unit 实现资源限制

这个老师没讲，以后研究下，应该也和cgroup有关

自定义tuned调优配置集

：

tuned 实现系统傻瓜化和集成化调优,操作系统预装多个调优场景配置集,这是一道RHCAS的考试题

查看调优策略

┌──[root@liruilongs.github.io]-[~] └─$ tuned-adm list Available profiles: - balanced - General non-specialized tuned profile - desktop - Optimize for the desktop use-case - latency-performance - Optimize for deterministic performance at the cost of increased power consumption - network-latency - Optimize for deterministic performance at the cost of increased power consumption, focused on low latency network performance - network-throughput - Optimize for streaming network throughput, generally only necessary on older CPUs or 40G+ networks - powersave - Optimize for low power consumption - throughput-performance - Broadly applicable tuning that provides excellent performance across a variety of common server workloads - virtual-guest - Optimize for running inside a virtual guest - virtual-host - Optimize for running KVM guests Current active profile: virtual-guest ┌──[root@liruilongs.github.io]-[~] └─$ tuned-adm recommend # 查看推荐的策略 virtual-guest ┌──[root@liruilongs.github.io]-[~] └─$ tuned-adm profile virtual-guest

调优策略位置

┌──[root@liruilongs.github.io]-[~] └─$ cd /usr/lib/tuned/;ls ## 调优参数 balanced latency-performance powersave virtual-guest desktop network-latency recommend.conf virtual-host functions network-throughput throughput-performance ┌──[root@liruilongs.github.io]-[/usr/lib/tuned] └─$ cd virtual-guest/ ┌──[root@liruilongs.github.io]-[/usr/lib/tuned/virtual-guest] └─$ ls tuned.conf ┌──[root@liruilongs.github.io]-[/usr/lib/tuned/virtual-guest] └─$ cat tuned.conf # # tuned configuration # [main] summary=Optimize for running inside a virtual guest include=throughput-performance [sysctl] # If a workload mostly uses anonymous memory and it hits this limit, the entire # working set is buffered for I/O, and any more write buffering would require # swapping, so it's time to throttle writes until I/O can catch up. Workloads # that mostly use file mappings may be able to use even higher values. # # The generator of dirty data starts writeback at this percentage (system default # is 20%) vm.dirty_ratio = 30 # Filesystem I/O is usually much more efficient than swapping, so try to keep # swapping low. It's usually safe to go even lower than this on systems with # server-grade storage. vm.swappiness = 30 ┌──[root@liruilongs.github.io]-[/usr/lib/tuned/virtual-guest] └─$

在/etc/tuned目录中编辑自定义tuned profile,配置集中的条目可以相互引用，并通过各种plugin自定义

获取 yum仓库的tuned profile

┌──[root@liruilongs.github.io]-[/usr/lib/tuned/virtual-guest] └─$ yum list | grep tuned tuned.noarch 2.8.0-5.el7 @anaconda tuned.noarch 2.11.0-11.el7_9 updates tuned-gtk.noarch 2.11.0-11.el7_9 updates tuned-profiles-atomic.noarch 2.11.0-11.el7_9 updates tuned-profiles-compat.noarch 2.11.0-11.el7_9 updates tuned-profiles-cpu-partitioning.noarch 2.11.0-11.el7_9 updates tuned-profiles-mssql.noarch 2.11.0-11.el7_9 updates tuned-profiles-oracle.noarch 2.11.0-11.el7_9 updates tuned-utils.noarch 2.11.0-11.el7_9 updates tuned-utils-systemtap.noarch 2.11.0-11.el7_9 updates ┌──[root@liruilongs.github.io]-[/usr/lib/tuned/virtual-guest] └─$ yum -y install tuned-profiles-oracle.noarch .... ┌──[root@liruilongs.github.io]-[/usr/lib/tuned/virtual-guest] └─$ tuned-adm list Available profiles: - balanced - General non-specialized tuned profile - desktop - Optimize for the desktop use-case - hpc-compute - Optimize for HPC compute workloads - latency-performance - Optimize for deterministic performance at the cost of increased power consumption - network-latency - Optimize for deterministic performance at the cost of increased power consumption, focused on low latency network performance - network-throughput - Optimize for streaming network throughput, generally only necessary on older CPUs or 40G+ networks - oracle - Optimize for Oracle RDBMS - powersave - Optimize for low power consumption - throughput-performance - Broadly applicable tuning that provides excellent performance across a variety of common server workloads - virtual-guest - Optimize for running inside a virtual guest - virtual-host - Optimize for running KVM guests Current active profile: virtual-guest ┌──[root@liruilongs.github.io]-[/usr/lib/tuned/virtual-guest] └─$

通过SystemTap配置内核模块进行系统底层分析：

嗯，这部分有些复杂，有些包需要订阅，先记录下，以后有机会学习

Linux

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