Add a section on performance tuning

And mention @nine7nine's Wine PKGBUILD as a good starting point for
using fsync.

README.md

@@ -26,6 +26,7 @@ compatibility while also staying easy to debug and maintain.
     - [Editor hosting modes](#editor-hosting-modes)
     - [Example](#example)
 - [Troubleshooting common issues](#troubleshooting-common-issues)
+- [Performance tuning](#performance-tuning)
 - [Runtime dependencies and known issues](#runtime-dependencies-and-known-issues)
 - [Building](#building)
   - [32-bit bitbridge](#32-bit-bitbridge)
@@ -330,6 +331,42 @@ group = "This will be ignored!"
   being able to start. There should be plugin output messages in your DAW or
   terminal that with more information on what went wrong.
 
+## Performance tuning
+
+Running Windows VST plugins under Wine should have minimal performance impact,
+but you may still notice an increase in latency and audio spikes. There are a
+few things you can do to get rid of most or all of these negative side effects:
+
+- First of all, you'll want to make sure that your user is able to run programs
+  with realtime privileges. Note that on Arch and Manjaro this does not
+  necessarily require a realtime kernel as the `PREMPT` patch set is enabled on
+  their regular kernels. You can verify that this is set up correctly by running
+  `chrt -f 10 whoami`, which should print your username.
+
+- The second, possibly even more important thing is to use a build of Wine with
+  Proton's fsync patches. This can improve performance significantly when using
+  a lot of plugins at once. If you're running Arch or Manjaro, then you can use
+  [this](https://github.com/nine7nine/pkgbuilds_nspa/tree/master/wine-nspa)
+  audio production optimized Wine PKGBUILD. Aside from a patched version of Wine
+  you'll also need a supported kernel for this to work. Manjaro's kernel
+  supports fsync out of the box, and on Arch you can use the `linux-zen` kernel.
+  Finally you'll have to set the `WINEFSYNC` environment variable to `1` to
+  enable fsync. See the [search path setup](#search-path-setup) section for more
+  information on where to do this. You can use the following command to check if
+  this is set correctly:
+
+  ```shell
+  env -i HOME="$HOME" $SHELL -l -c "echo $WINEFSYNC"
+  ```
+
+  If this prints `1` then everything is set up correctly. You'll have to log out
+  and back in again for this to take effect on applications launched from the
+  GUI.
+
+  I don't know the what the best way to install an fsync patched version of Wine
+  on other distros is, so if anyone knows more about this then please let me
+  know and I'll add it to this section.
+
 ## Runtime dependencies and known issues
 
 Any VST2 plugin should function out of the box, although some plugins will need