Merge pull request #568 from jakobzierk/patch-2

Windows/VirtualBox performance

doc/troubleshooting.rst

@@ -140,6 +140,29 @@ This indicates an error in the internal accounting of
 preprocessing. Please file a bug report.
 
 
+Windows/VirtualBox performance
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Performance when using Windows/VirtualBox is by default abysmal, as
+AVX/AVX2 instructions are deactivated (see e.g.
+`here <https://stackoverflow.com/questions/65780506/how-to-enable-avx-avx2-in-virtualbox-6-1-16-with-ubuntu-20-04-64bit>`_),
+which causes a dramatic performance loss. Deactivate Hyper-V/Hypervisor
+using::
+  bcdedit /set hypervisorlaunchtype off
+  DISM /Online /Disable-Feature:Microsoft-Hyper-V
+
+
+Performance can be further increased when compiling MP-SPDZ yourself:
+::
+ sudo apt-get update
+ sudo apt-get install automake build-essential git libboost-dev libboost-thread-dev libntl-dev libsodium-dev libssl-dev libtool m4 python3 texinfo yasm
+ git clone https://github.com/data61/MP-SPDZ.git
+ cd MP-SPDZ
+ make tldr
+
+See also `this issue <https://github.com/data61/MP-SPDZ/issues/557>`_ for a discussion.
+
+
 ``mac_fail``
 ~~~~~~~~~~~~