GitLab / Using Strace to Understand GitLab

Walkthrough of what an strace of a typical request in Puma looks like, and a quick comparison on how Unicorn is different.

Part 1: https://www.youtube.com/watch?v=fcY5pPUq35U
Part 2: https://www.youtube.com/watch?v=tThs8QeP2qY
Part 4: https://www.youtube.com/watch?v=dgJH4wpR5OE

A walkthrough of straces of two Gitaly requests.

0:00 FindCommit - a typical Gitaly RPC
8:04 UserCommitFiles - complex Gitaly-Ruby RPC
12:08 Gitaly InfoRefs cache invalidation
15:26 GitalyRuby requests to main Gitaly process
20:10 Pre-receive hooks
28:55 Update hooks
34:00 Post-receive hooks
37:39 Regenerate InfoRefs cache

Part 1: https://www.youtube.com/watch?v=fcY5pPUq35U
Part 2: https://www.youtube.com/watch?v=tThs8QeP2qY
Part 3: https://www.youtube.com/watch?v=J-GkU7Mmqy4

Start of a series describing how to use Strace to understand how programs work internally.

0:00 Intro
0:28 What is strace
1:50 When not to use strace
3:08 Tracing 'ls -la'
5:25 execve
7:33 open
9:00 stat
9:48 mmap
14:18 mprotect
21:05 Summary

Strace man page: https://man7.org/linux/man-pages/man1/strace.1.html

Brendan Gregg article on performance impacts of strace: http://www.brendangregg.com/blog/2014-05-11/strace-wow-much-syscall.html

Part 2: https://www.youtube.com/watch?v=tThs8QeP2qY
Part 3: https://www.youtube.com/watch?v=J-GkU7Mmqy4
Part 4: https://www.youtube.com/watch?v=dgJH4wpR5OE

Walkthrough on using Strace to understand how Git interacts with the filesystem.

0:00 Intro
1:00 Tracing 'git status'
10:20 Tracing 'git commit'

Part 1: https://www.youtube.com/watch?v=fcY5pPUq35U
Part 3: https://www.youtube.com/watch?v=J-GkU7Mmqy4
Part 4: https://www.youtube.com/watch?v=dgJH4wpR5OE