RHCA-RH442(性能调优)学习笔记

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RHCA 442-1(1)

  1. Business Level Tuning > Application Level Tuning > Kernel Level Tuning(RH442)
  2. grep CPU /proc/cpuinfo
  3. lscpu
    a. lscpu -p
  4. cat /proc/cpuinfo
    a. cat /proc/meminfo
    RHCA 442-1(2)
  5. dmesg(实时kernel信息)
  6. /var/log/dmesg(开机kernel信息写入)
  7. getconf -a
  8. x85info(yum install x86info -y)
  9. dmidecode
    a. dmidecode -t 0
  10. cd /sys/class/dmi/id/
  11. lspci
    a. lspci -v
    b. lspci -vv
    c. lspci -vvv
  12. lsusb
    a. lsusb -v
  13. ethtool eth0
  14. powertop(yum install powertop -y)
  15. sosreport
    RHCA 442-2(1)
  16. K=1000
    a. Ki=1024
  17. vmstat
    a. vmstat 1 5
    b. dd if=/dev/zero of=/dev/null
    c. buffer= buffer cache(文件描述数据)
    d. cache= page cache(文件内容数据)
    e. echo 3 > /proc/sys/vm/drop_cahces
    f. bi= block in
    g. bo= block out
  18. iostat
    a. iostat -x sda 1
  19. mpstat
    a. mpstat 1
    b. mpstat -p 0 1
  20. sar
    a. yum install sysstat
    b. cat /etc/cron.d/sysstat
    c. LANG=C sar -q(CPU负载)
    d. LANG=C sar -b(I/O状况)
    i. sar -b -s 17:00:00 -e 19:00:00
    e. LANG=C sar -p 0 (第一颗cpu状态)
    f. LAMD=C sar -d(磁盘状态)
    g. LANG=C sar -n DEV|EDEV(网络信息)
    h. cd /var/log/sa/
    i. cat /etc/sysconfig/sysstat
  21. awk
    a. awk -F: ‘{print $1}’ /etc/passwd
    b. df -P | awk ‘{print $1 “ is mount on “ $NF}’
    c. awk -F: ‘BEGIN{print “User List:”} {print $1} END{print “Done.”}’ /etc/passwd
    d. df -hP | awk ‘BEGIN{print “File System status:”}{print $1,$(NF-2)} END{print “Done.”}’
    e. awk -F: ‘/^r/ {print $1}’ /etc/passwd
    f. awk -F: ‘/^[a-z]t:./ {print $1}’ /etc/passwd
    g. sar -q | awk ‘/^[^a-z]+$/{print $1,$4,$5,$6}’ > /tmp/cpudata
  22. gnuplot
    a. yum install gnuplot -t
    b. gnuplot
    i. set xdata tim
ii. set timefmt "%H:%M:%S"
iii. plot "/tmp/cpudata" using 1:2 with lines

RHCA 442-2(2)

  1. Little’s Law
  2. L(lenth) = A(arrival time)* W(wait time)
  3. W(wait time) = Q(queue time) +S(service time)
  4. S(service time) = St(sys time) + Ut(user time)
  5. time command
    a. time updatedb
    b. echo 3 > /proc/sys/vm/drop_caches
    c. time updatedb
    RHCA 442-3(1-2)
  6. lsmod
    a. ls /lib/modules/3.10.0-327.el7.x86_64/ (kernel模块)
    b. ll /boot/vmlinuz-3.10.0-327.el7.x86_64 (kernel本身)
  7. modinfo
    a. modinfo st
    b. modinfo -p st
    c. modinfo usb_storage
    d. modinfo sx8
  8. modprobe
    a. modprobe st
  9. rmmod
    a. rmmod st
  10. /etc/modprobe.d/my.conf
    a. options usb_storage delay_user = 3
    b. options st buffer_kbs = 64
    c. options sx8 max_queue = 15
  11. /sys/module/$(mname)/paraments/$(pname)
    a. more /sys/module/usb_storage/parameters/delay_use
  12. more /etc/sysconfig/modules/st.modules (开机模块加载)
  13. I/O Schedulers
    a. cfq,deadline,anticipatory,noop
    b. cat /sys/block/sda/queue/scheduler ([]中是当前电梯算法)
    c. more /sys/block/sda/queue/nr_requests
    d. more /sys/block/sda/queue/read_ahead_kb
    e. echo cfq > /sys/block/sda/queue/scheduler
    f. more /sys/block/sda/queue/scheduler
    g. ll /sys/block/sda/queue/iosched
    RHCA 442-3(3)
  14. tuned
    a. yum info tuned
    b. yum install tuned -y
    c. tuned-adm active
    d. tuned-adm list
    e. tuned-adm profile desktop
    f. ll /usr/lib/tuned/
    g. cp -a /usr/lib/tuned/desktop/* /etc/tuned/ex442/
    RHCA 442-4(1)
  15. CPU Scheduling
  16. CFS Scheduler
    a. virtual time
  17. chrt command
    a. chrt -f 10 top
    b. chrt -r 1 md5sum /dev/zero
    RHCA 442-4(2)
  18. x86info -c
  19. valgrind -tool=cahcegrind command1
  20. perf stat -e cahce-misses command
    RHCA 442-4(3-4)
  21. pam_limits
    a. vi /etc/security/limits.conf
    i. user    hard        cpu        1
    b. ulimit -a
    c. cgroup
    i. service cgconfig start
ii. service cgred start
iii. lssubsys -m
iv. echo 0 > /sys/devices/system/cpu/cpu1/online (下线cpu)
v. mount -t tmpfs none /mnt/tmpfs (物理内存挂成分区)
    RHCA 442-5(1)
  22. strace
    a. kernel space(system call)
    b. strace updatedb
    c. strace -e trace=network ping -c1 i
    d. strace -e trace=file ls /
    e. strace -p 1
    f. strace -c updatedb
  23. ltrace
    a. user space(library call [glibc])
    b. ltrace updatedb
    c. ltrace ls /
  24. systemtap
    a. yum install kernel-debuginfo -y
    i. yum install systemtap
ii. stap -c /usr/share/doc/systemtap-client-3.0/examples/profiling/topsys.stp
    b. stap -v abc.stap
    c. staprun abc.ko
    d. stapusr group
    e. stapdev group
    RHCA 442-5(2)
  25. Paging
    a. pages，x86 normal page size is 4KiB
    b. getconf PAGE_SIZE
  26. VSZ
  27. RSS
  28. TLB
  29. mount -t hugetlbfs none /muntpoint
  30. Tune per-BDI Flush Threads
    a. vm.dirty_expire_centisecs
    b. vm.dirty_writeback_centisecs
  31. Oou of Menory(OOM)
  32. Memory Overcommit
    a. sysctl -p | grep overcommit_memory
    b. sysctl -p | grep overcommit_ratio
    c. grep Coomitted_AS /proc/meminfo
  33. SysV IPC
    a. ipcs
    b. ipcs -l
    c. Tune Semaphores
    d. Message queues
    e. Shared memory
    i. kernel.shmmni
ii. kernel.shmmax
iii. kernel.shmall
    RHCA 442-6(1)
  34. File Systems
    a. EXT3
    b. EXT4
    c. XFS
    d. BTRFS
  35. External Journaling
    a. mkfs.ext4 -O journal_dev -b 4096 /dev/vdb1
    b. mkfs.ext4 -J device=/dev/vdb1 -b 4096 /dev/vda3
    c. blkid
    RHCA 442-6(2)
  36. yum install qperf
  37. sysctl net.ipv4.tcp_low_latency
  38. net.ipv4.tcp_mem/net.ipv4.udp_mem(单位pages)
  39. tc qdisc show

  40. Bonding mode
    a. balance-rr: mode 0
    b. actice-backup: mode 1
    c. 802.3ad: mode 4(工作在2层，需要配交换机)
    d. cat /proc/net/bonding/bond0

  41. MTU(最大传输单元 default 1500bytes)
    a. TCP protocol headers 52 (52/1500=3.5% overhead)
    b. TDP protocol headers 28 (28/1500=1.9% overhead)
    c. Jumbo Frames (MTU bigger that 1500 需要配置交换机)

    i. Official maximum size is 9000 bytes (52/9000=0.58% overhead
ii. vi /etc/sysconfig/network-scripts/ifcfg/eth0==》"MTU=9000"