diff --git a/README.md b/README.md
index a98d5aa0..ad46464b 100644
--- a/README.md
+++ b/README.md
@@ -263,6 +263,7 @@ the Wine prefix. Removing the option will revert to the previous behavior.
 | <tt>nod3d11</tt>      | <tt>PROTON_NO_D3D11</tt>       | Disable <tt>d3d11.dll</tt>, for d3d11 games which can fall back to and run better with d3d9. |
 | <tt>nod3d10</tt>      | <tt>PROTON_NO_D3D10</tt>       | Disable <tt>d3d10.dll</tt> and <tt>dxgi.dll</tt>, for d3d10 games which can fall back to and run better with d3d9. |
 | <tt>noesync</tt>      | <tt>PROTON_NO_ESYNC</tt>       | Do not use eventfd-based in-process synchronization primitives. |
+| <tt>nofsync</tt>      | <tt>PROTON_NO_FSYNC</tt>       | Do not use futex-based in-process synchronization primitives. (Automatically disabled on systems with no `FUTEX_WAIT_MULTIPLE` support.) |
 | <tt>forcelgadd</tt>   | <tt>PROTON_FORCE_LARGE_ADDRESS_AWARE</tt> | Force Wine to enable the LARGE_ADDRESS_AWARE flag for all executables. |
 | <tt>oldglstr</tt>     | <tt>PROTON_OLD_GL_STRING</tt>  | Set some driver overrides to limit the length of the GL extension string, for old games that crash on very long extension strings. |
 
diff --git a/proton b/proton
index 4dbf1d8b..fd7195e2 100755
--- a/proton
+++ b/proton
@@ -269,12 +269,16 @@ check_environment("PROTON_USE_D9VK", "d9vk")
 check_environment("PROTON_NO_D3D11", "nod3d11")
 check_environment("PROTON_NO_D3D10", "nod3d10")
 check_environment("PROTON_NO_ESYNC", "noesync")
+check_environment("PROTON_NO_FSYNC", "nofsync")
 check_environment("PROTON_FORCE_LARGE_ADDRESS_AWARE", "forcelgadd")
 check_environment("PROTON_OLD_GL_STRING", "oldglstr")
 
 if not "noesync" in config_opts:
     env["WINEESYNC"] = "1"
 
+if not "nofsync" in config_opts:
+    env["WINEFSYNC"] = "1"
+
 if "oldglstr" in config_opts:
     #mesa override
     env["MESA_EXTENSION_MAX_YEAR"] = "2003"