From d023342165a0e3bc3e8e2f34b70a5b928cdf52aa Mon Sep 17 00:00:00 2001
From: ClashSAN <98228077+ClashSAN@users.noreply.github.com>
Date: Sun, 30 Oct 2022 09:43:03 +0000
Subject: [PATCH] Added tip (from @aliencaocao) to install ninja to the
 @duckness guide

---
 Xformers.md | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/Xformers.md b/Xformers.md
index 8cdbe99..30e4589 100644
--- a/Xformers.md
+++ b/Xformers.md
@@ -64,7 +64,23 @@ pip install wheel
 
 7. You can finally build xFormers, note that the build will take a long time (probably 10-20minutes), it may initially complain of some errors but it should still compile correctly. 
 
-```sh
+> OPTIONAL tip: To further speed up on multi-core CPU Windows systems, install ninja https://github.com/ninja-build/ninja.
+> Steps to install:
+> 1. download ninja-win.zip from https://github.com/ninja-build/ninja/releases and unzip
+> 2. place ninja.exe under C:\Windows OR add the full path to the extracted ninja.exe into system PATH
+> 3. Run ninja -h in cmd and verify if you see a help message printed
+> 4. Run the follow commands to start building. It should automatically use Ninja, no extra config is needed. You should see significantly higher CPU usage (40%+).
+> ```
+> python setup.py build
+> python setup.py bdist_wheel
+> ```
+> This has reduced build time on a windows PC with a AMD 5800X CPU from 1.5hr to 10min.
+> Ninja is also supported on Linux and MacOS but I do not have these OS to test thus can not provide step-by-step tutorial.
+
+
+
+8. Run the following:
+ ```sh
 python setup.py build
 python setup.py bdist_wheel
 ```