Recommend installing python3-yaml as distro package
The Python yaml package (pyyaml) can optionally use a YAML parser/dumper
written in C called LibYAML. This library is roughly 10x faster than the
fallback implementation written in Python. Since fusesoc (and fusesoc
generators) use YAML quite extensively, switching to a faster YAML
implementation decreases build and simulation times measurably (10s of
seconds in my tests).
pip can install pyyaml with LibYAML support as long as the Python
development headers, a C compiler, and LibYAML are present. Or we can
avoid compiling the package on a user's machine, and use a precompiled
version provided by the distribution. That's what this patch is doing.
The pip version is still available as fallback in
python-requirements.txt for users not installing all requirements
from the apt-requirements.txt file (or the user guide, which uses this
information as well).
Signed-off-by: Philipp Wagner <phw@lowrisc.org>
diff --git a/apt-requirements.txt b/apt-requirements.txt
index 17b85d4..afb46e8 100644
--- a/apt-requirements.txt
+++ b/apt-requirements.txt
@@ -24,6 +24,9 @@
python3-pip
python3-setuptools
python3-wheel
+# The pip-installed version does not come with LibYAML support by default,
+# which significantly speeds up the parsing/dumping of YAML files in fusesoc.
+python3-yaml
srecord
tree
zlib1g-dev
