_index.md

title	Optimize AArch64 code with LLVM LTO and PGO
description	Learn how to use LLVM Link-Time Optimization and Profile-Guided Optimization on AArch64 Linux.
minutes_to_complete	45
aliases	/learning-paths/servers-and-cloud-computing/pgo-test/
who_is_this_for	This is an introductory topic for developers who compile C or C++ applications on AArch64 Linux and want to use Link-Time Optimization (LTO) with Profile-Guided Optimization (PGO).
learning_objectives	Understand the basics of Link-Time Optimization (LTO) and Profile-Guided Optimization (PGO) Build Thin-LTO and Full-LTO binaries with Clang on AArch64 Generate instrumentation-based profile data with Clang on AArch64 Generate sample-based profile data with Clang on AArch64 Use generated profile data to optimize a small example application
prerequisites	LLVM installed with Clang, LLD, `llvm-profdata`, and `llvm-profgen` available in your `PATH`. For setup instructions, see [LLVM toolchain for Linux on Arm](/install-guides/llvm/). Linux kernel version 6.17 or later for the Branch Record Buffer Extension (BRBE) profile-guided optimization workflow
author	Paschalis Mpeis
skilllevels	Introductory
subjects	Performance and Architecture
armips	Neoverse Cortex-A
tools_software_languages	Clang LLVM LTO PGO perf
operatingsystems	Linux
further_reading	resource title link type Clang profile-guided optimization https://clang.llvm.org/docs/UsersManual.html#profile-guided-optimization documentation resource title link type llvm-profdata command guide https://llvm.org/docs/CommandGuide/llvm-profdata.html documentation resource title link type llvm-profgen command guide https://llvm.org/docs/CommandGuide/llvm-profgen.html documentation resource title link type LLVM LTO https://llvm.org/docs/LinkTimeOptimization.html documentation resource title link type LLVM Thin-LTO https://clang.llvm.org/docs/Thin-LTO.html documentation
weight	1
layout	learningpathall
learning_path_main_page	yes