December | 2020

To be able to get a more detailed information about your current linux distribution, including the code names use the following:

kosmas:$ cat /etc/os-release
NAME="Ubuntu"
VERSION="18.04.5 LTS (Bionic Beaver)"
ID=ubuntu
ID_LIKE=debian
PRETTY_NAME="Ubuntu 18.04.5 LTS"
VERSION_ID="18.04"
HOME_URL="https://www.ubuntu.com/"
SUPPORT_URL="https://help.ubuntu.com/"
BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/"
PRIVACY_POLICY_URL="https://www.ubuntu.com/legal/terms-and-policies/privacy-policy"
VERSION_CODENAME=bionic
UBUNTU_CODENAME=bionic

BASH<br>
​x
 
kosmas:$ cat /etc/os-releaseNAME="Ubuntu"VERSION="18.04.5 LTS (Bionic Beaver)"ID=ubuntuID_LIKE=debianPRETTY_NAME="Ubuntu 18.04.5 LTS"VERSION_ID="18.04"HOME_URL="https://www.ubuntu.com/"SUPPORT_URL="https://help.ubuntu.com/"BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/"PRIVACY_POLICY_URL="https://www.ubuntu.com/legal/terms-and-policies/privacy-policy"VERSION_CODENAME=bionicUBUNTU_CODENAME=bionic​

There is a very nice example on the O’reilly ‘Linux Under The Hood’ training about using strace to compare performance of two commands that provide the same output but with different calls. The two different commands were: ls and echo *, that they both provide the listing of the current directory.

First using the strace with ls:

kosmas:$ strace -c ls
abi-4.13.0-45-generic      config-4.4.0-31-generic        initrd.img-4.4.0-31-generic   System.map-4.15.0-123-generic         vmlinuz-4.15.0-123-generic
abi-4.13.0-46-generic      efi                            memtest86+.bin                System.map-4.15.0-124-generic         vmlinuz-4.15.0-124-generic
abi-4.4.0-31-generic       grub                           memtest86+.elf                System.map-4.15.0-126-generic         vmlinuz-4.15.0-126-generic
config-4.13.0-45-generic   initrd.img-4.13.0-45-generic   memtest86+_multiboot.bin      System.map-4.4.0-31-generic           vmlinuz-4.4.0-31-generic
config-4.13.0-46-generic   initrd.img-4.13.0-46-generic   retpoline-4.13.0-45-generic   vmlinuz-4.13.0-45-generic             vmlinuz-4.4.0-31-generic.efi.signed
config-4.15.0-123-generic  initrd.img-4.15.0-123-generic  retpoline-4.13.0-46-generic   vmlinuz-4.13.0-45-generic.efi.signed
config-4.15.0-124-generic  initrd.img-4.15.0-124-generic  System.map-4.13.0-45-generic  vmlinuz-4.13.0-46-generic
config-4.15.0-126-generic  initrd.img-4.15.0-126-generic  System.map-4.13.0-46-generic  vmlinuz-4.13.0-46-generic.efi.signed
% time     seconds  usecs/call     calls    errors syscall
------ ----------- ----------- --------- --------- ----------------
 15.81    0.000095          12         8           write
 14.64    0.000088           7        12           mprotect
 13.48    0.000081           5        17           mmap
  9.98    0.000060           7         9           openat
  7.82    0.000047           4        11           close
  7.32    0.000044          22         2           getdents
  6.82    0.000041           6         7           read
  5.66    0.000034           3        10           fstat
  4.99    0.000030           4         8         8 access
  3.16    0.000019          10         2         2 statfs
  2.00    0.000012          12         1           munmap
  1.83    0.000011           4         3           brk
  1.66    0.000010           5         2           ioctl
  1.50    0.000009           5         2           rt_sigaction
  0.67    0.000004           4         1           rt_sigprocmask
  0.67    0.000004           4         1           arch_prctl
  0.67    0.000004           4         1           set_tid_address
  0.67    0.000004           4         1           set_robust_list
  0.67    0.000004           4         1           prlimit64
  0.00    0.000000           0         1           execve
------ ----------- ----------- --------- --------- ----------------
100.00    0.000601                   100        10 total

SHELL
 
kosmas:$ strace -c lsabi-4.13.0-45-generic      config-4.4.0-31-generic        initrd.img-4.4.0-31-generic   System.map-4.15.0-123-generic         vmlinuz-4.15.0-123-genericabi-4.13.0-46-generic      efi                            memtest86+.bin                System.map-4.15.0-124-generic         vmlinuz-4.15.0-124-genericabi-4.4.0-31-generic       grub                           memtest86+.elf                System.map-4.15.0-126-generic         vmlinuz-4.15.0-126-genericconfig-4.13.0-45-generic   initrd.img-4.13.0-45-generic   memtest86+_multiboot.bin      System.map-4.4.0-31-generic           vmlinuz-4.4.0-31-genericconfig-4.13.0-46-generic   initrd.img-4.13.0-46-generic   retpoline-4.13.0-45-generic   vmlinuz-4.13.0-45-generic             vmlinuz-4.4.0-31-generic.efi.signedconfig-4.15.0-123-generic  initrd.img-4.15.0-123-generic  retpoline-4.13.0-46-generic   vmlinuz-4.13.0-45-generic.efi.signedconfig-4.15.0-124-generic  initrd.img-4.15.0-124-generic  System.map-4.13.0-45-generic  vmlinuz-4.13.0-46-genericconfig-4.15.0-126-generic  initrd.img-4.15.0-126-generic  System.map-4.13.0-46-generic  vmlinuz-4.13.0-46-generic.efi.signed% time     seconds  usecs/call     calls    errors syscall------ ----------- ----------- --------- --------- ---------------- 15.81    0.000095          12         8           write 14.64    0.000088           7        12           mprotect 13.48    0.000081           5        17           mmap  9.98    0.000060           7         9           openat  7.82    0.000047           4        11           close  7.32    0.000044          22         2           getdents  6.82    0.000041           6         7           read  5.66    0.000034           3        10           fstat  4.99    0.000030           4         8         8 access  3.16    0.000019          10         2         2 statfs  2.00    0.000012          12         1           munmap  1.83    0.000011           4         3           brk  1.66    0.000010           5         2           ioctl  1.50    0.000009           5         2           rt_sigaction  0.67    0.000004           4         1           rt_sigprocmask  0.67    0.000004           4         1           arch_prctl  0.67    0.000004           4         1           set_tid_address  0.67    0.000004           4         1           set_robust_list  0.67    0.000004           4         1           prlimit64  0.00    0.000000           0         1           execve------ ----------- ----------- --------- --------- ----------------100.00    0.000601                   100        10 total

And using the same with echo *

kosmas:$ strace -c echo *
abi-4.13.0-45-generic abi-4.13.0-46-generic abi-4.4.0-31-generic config-4.13.0-45-generic config-4.13.0-46-generic config-4.15.0-123-generic config-4.15.0-124-generic config-4.15.0-126-generic config-4.4.0-31-generic efi grub initrd.img-4.13.0-45-generic initrd.img-4.13.0-46-generic initrd.img-4.15.0-123-generic initrd.img-4.15.0-124-generic initrd.img-4.15.0-126-generic initrd.img-4.4.0-31-generic memtest86+.bin memtest86+.elf memtest86+_multiboot.bin retpoline-4.13.0-45-generic retpoline-4.13.0-46-generic System.map-4.13.0-45-generic System.map-4.13.0-46-generic System.map-4.15.0-123-generic System.map-4.15.0-124-generic System.map-4.15.0-126-generic System.map-4.4.0-31-generic vmlinuz-4.13.0-45-generic vmlinuz-4.13.0-45-generic.efi.signed vmlinuz-4.13.0-46-generic vmlinuz-4.13.0-46-generic.efi.signed vmlinuz-4.15.0-123-generic vmlinuz-4.15.0-124-generic vmlinuz-4.15.0-126-generic vmlinuz-4.4.0-31-generic vmlinuz-4.4.0-31-generic.efi.signed
% time     seconds  usecs/call     calls    errors syscall
------ ----------- ----------- --------- --------- ----------------
  0.00    0.000000           0         1           read
  0.00    0.000000           0         1           write
  0.00    0.000000           0         5           close
  0.00    0.000000           0         4           fstat
  0.00    0.000000           0         6           mmap
  0.00    0.000000           0         4           mprotect
  0.00    0.000000           0         1           munmap
  0.00    0.000000           0         3           brk
  0.00    0.000000           0         3         3 access
  0.00    0.000000           0         1           execve
  0.00    0.000000           0         1           arch_prctl
  0.00    0.000000           0         3           openat
------ ----------- ----------- --------- --------- ----------------
100.00    0.000000                    33         3 total

SHELL
 
kosmas:$ strace -c echo *abi-4.13.0-45-generic abi-4.13.0-46-generic abi-4.4.0-31-generic config-4.13.0-45-generic config-4.13.0-46-generic config-4.15.0-123-generic config-4.15.0-124-generic config-4.15.0-126-generic config-4.4.0-31-generic efi grub initrd.img-4.13.0-45-generic initrd.img-4.13.0-46-generic initrd.img-4.15.0-123-generic initrd.img-4.15.0-124-generic initrd.img-4.15.0-126-generic initrd.img-4.4.0-31-generic memtest86+.bin memtest86+.elf memtest86+_multiboot.bin retpoline-4.13.0-45-generic retpoline-4.13.0-46-generic System.map-4.13.0-45-generic System.map-4.13.0-46-generic System.map-4.15.0-123-generic System.map-4.15.0-124-generic System.map-4.15.0-126-generic System.map-4.4.0-31-generic vmlinuz-4.13.0-45-generic vmlinuz-4.13.0-45-generic.efi.signed vmlinuz-4.13.0-46-generic vmlinuz-4.13.0-46-generic.efi.signed vmlinuz-4.15.0-123-generic vmlinuz-4.15.0-124-generic vmlinuz-4.15.0-126-generic vmlinuz-4.4.0-31-generic vmlinuz-4.4.0-31-generic.efi.signed% time     seconds  usecs/call     calls    errors syscall------ ----------- ----------- --------- --------- ----------------  0.00    0.000000           0         1           read  0.00    0.000000           0         1           write  0.00    0.000000           0         5           close  0.00    0.000000           0         4           fstat  0.00    0.000000           0         6           mmap  0.00    0.000000           0         4           mprotect  0.00    0.000000           0         1           munmap  0.00    0.000000           0         3           brk  0.00    0.000000           0         3         3 access  0.00    0.000000           0         1           execve  0.00    0.000000           0         1           arch_prctl  0.00    0.000000           0         3           openat------ ----------- ----------- --------- --------- ----------------100.00    0.000000                    33         3 total

So the difference in time is 0.00000 for the echo and 0.000601 for the ls.

Similarly the number of calls for the echo is 33, but ls is using 100.

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Web notebook about thoughts and discoveries in DevOps, SRE, Software Engineering….

Monthly Archives: December 2020

Getting detailed information about your Linux distribution

Displaying timestamps in dmesg output

Using strace for analyzing performance