[llvm] [BOLT][docs] Add merge-fdata to Linux optimization guide (PR #97659)

[Maksim Panchenko via llvm-commits]

https://github.com/maksfb created https://github.com/llvm/llvm-project/pull/97659

None

>From 22ab5136ce23721ea036c89f56117db75632fe55 Mon Sep 17 00:00:00 2001
From: Maksim Panchenko <maks at fb.com>
Date: Wed, 3 Jul 2024 17:20:55 -0700
Subject: [PATCH] [BOLT][docs] Add merge-fdata to Linux optimization guide

---
 bolt/docs/OptimizingLinux.md | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/bolt/docs/OptimizingLinux.md b/bolt/docs/OptimizingLinux.md
index 1fffcf2252906..0045f0ead9fd0 100644
--- a/bolt/docs/OptimizingLinux.md
+++ b/bolt/docs/OptimizingLinux.md
@@ -44,6 +44,11 @@ $ perf2bolt -p perf.data -o perf.fdata vmlinux
 
 Under a high load, `perf.data` should be several gigabytes in size and you should expect the converted `perf.fdata` not to exceed 100 MB.
 
+Profiles collected from multiple workloads could be joined into a single profile using `merge-fdata` utility:
+```bash
+$ merge-fdata perf.1.fdata perf.2.fdata ... perf.<N>.fdata > perf.merged.fdata
+```
+
 Two changes are required for the kernel build. The first one is optional but highly recommended. It introduces a BOLT-reserved space into `vmlinux` code section: