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KirillLykov / system-performance.md
Last active January 3, 2026 20:55
Systems performance book by B. Gregg

Summary for Systems Performance book by Brendan Gregg

Book it sel on o'reilly

OS-related things

  • Kernel -- software that manages the system by providing access to hardware and other resources (memory, network stack, scheduling cpu, etc). Runs in priveleged CPU mode -- kernel mode. It uses kernel-space stack.
  • Process -- an OS abstraction for running programs. Runs in user mode with access to kernel mode via system calls. It consists of: memory address space, file descriptors, thread stacks, registers. Process uses user-space stacks. For example, syscalls use a s kernel exception stack associated with each thread.