[Bug 43277] Far Cry 3 has poor performance (Ryzen CPU-specific issue?)

[WineHQ Bugzilla]

https://bugs.winehq.org/show_bug.cgi?id=43277

--- Comment #48 from Hans Leidekker  ---
Created attachment 65276
  --> https://bugs.winehq.org/attachment.cgi?id=65276
hack

Here's a hack that allows you to restrict Wine processes to a subset of the
available cores. You can pass a CPU mask through the WINECPUMASK environment
variable:

$ WINECPUMASK=0xff wine ...

This will tie Wine processes (including wineserver) to the first 8 cores. It
will also limit the number of reported cores to 8.

To get a performance gain on Ryzen the mask should specify the cores of one
core complex (CCX). Here's little bash script that computes the mask for the
first CCX:

#!bin/bash
cat /proc/cpuinfo | grep "^model name" | grep "AMD Ryzen" >/dev/null 2>&1

if [ $? -eq 0 ];
then
    NUM_CPUS=$(cat /proc/cpuinfo | grep ^processor | wc -l)
    echo "found $NUM_CPUS AMD Ryzen cores"

CCX_MASK=$(((1 << $NUM_CPUS / 2) - 1))
    echo -n "first CCX mask: "
    printf "0x%x\n" $CCX_MASK
fi

With this patch The Forest goes from 23 to 40 fps on a 16 core Ryzen CPU. It
would be interesting to see if this also makes difference for the games
mentioned here and in duplicate reports.