From b5cf7bf7c5fa12e26846b360e2115c83a3b0ac88 Mon Sep 17 00:00:00 2001
From: paugier <pierre.augier@univ-grenoble-alpes.fr>
Date: Fri, 12 Jan 2024 13:53:29 +0100
Subject: [PATCH] Build option for perf and not portable

---
 doc/build-from-source.md | 17 +++++++++++++----
 meson.build              |  5 ++++-
 meson.options            | 23 +++++++++++++++++------
 noxfile.py               |  6 ++++--
 4 files changed, 38 insertions(+), 13 deletions(-)

diff --git a/doc/build-from-source.md b/doc/build-from-source.md
index b06aa90d..f15cbe53 100644
--- a/doc/build-from-source.md
+++ b/doc/build-from-source.md
@@ -97,6 +97,16 @@ There are 3 levels:
 
 ```
 
+````{important}
+
+One can activate a performance oriented and not portable build using:
+
+```sh
+pip install . -v -C setup-args=-Dnative=true
+```
+
+````
+
 ````{note}
 
 Recent versions of `pip` allow one to specify different options like so:
@@ -107,7 +117,6 @@ pip install . -v \
   -C setup-args=-Duse-xsimd=false
 ```
 
-
 ````
 
 Of course, one can also change values of
@@ -140,8 +149,7 @@ pip install . -v -C setup-args=-Doptimization=2
 ```{admonition} Advanced compilation configuration
 
 The environment variables `CC`, `CXX`, `CFLAGS`, `CXXFLAGS` and `LDFLAGS`
-are honored. So for example, one could compile with
-`CXXFLAGS="-march=native -Ofast"`.
+are honored.
 
 Note that Fluidsim builds are not sensible to the [`~/.pythranrc` file](pythranrc)!
 
@@ -157,7 +165,8 @@ Note that Fluidsim builds are not sensible to the [`~/.pythranrc` file](pythranr
 - How to differentiate a native build from a
   regular build to produce binaries usable on other computers?
 
-  ???
+  By default the produced wheels should be portable. There is the `native`
+  build option to target the exact CPU used for compilation.
 
 - How to produce a wheel for other architectures (cross-compilation)?
 
diff --git a/meson.build b/meson.build
index 4100bfa1..47aa4c6e 100644
--- a/meson.build
+++ b/meson.build
@@ -83,12 +83,15 @@ print(incdir)'''
     )
   endif
 
-
   pythran_complex_hook = get_option('pythran-complex-hook')
   if pythran_complex_hook == 'os-dependent'
     pythran_complex_hook = host_machine.system() == 'linux'
   endif
 
+  if get_option('native')
+    cpp_args_pythran += ['-march=native', '-Ofast']
+  endif
+
 endif
 
 subdir('fluidsim')
diff --git a/meson.options b/meson.options
index ff44f3cd..b5c8ca59 100644
--- a/meson.options
+++ b/meson.options
@@ -4,13 +4,24 @@ option(
     value: 'pythran,python,numba',
     description:
       'pythran,python,numba (default), cython, numpy, numba; ' +
-      'or comma separated value representing multi-backends'
+      'or comma separated value representing multi-backends',
+)
+option(
+    'native',
+    type: 'boolean',
+    value: true,
+    description: 'Performance oriented and not portable build',
+)
+option(
+    'use-xsimd',
+    type: 'boolean',
+    value: true,
+    description: 'Turns on xsimd vectorization'
 )
-option('use-xsimd', type: 'boolean', value: true, description: 'Use xsimd')
 option(
     'pythran-complex-hook',
-    type : 'combo',
-    choices : ['os-dependent', 'true', 'false'],
-    value : 'os-dependent',
-    description: 'Pythran complex_hook option'
+    type: 'combo',
+    choices: ['os-dependent', 'true', 'false'],
+    value: 'os-dependent',
+    description: 'Pythran complex_hook option',
 )
diff --git a/noxfile.py b/noxfile.py
index 3a1d2b3d..1593e3c8 100644
--- a/noxfile.py
+++ b/noxfile.py
@@ -14,7 +14,9 @@ def validate_code(session):
 def test_without_fft_and_pythran(session):
     command = "pdm install -G dev -G test -G mpi --no-self"
     session.run_always(*command.split(), external=True)
-    session.install(".", "--config-settings=setup-args=-Dtransonic-backend=python", "--no-deps")
+    session.install(
+        ".", "--config-settings=setup-args=-Dtransonic-backend=python", "--no-deps"
+    )
     session.run(
         "make",
         "_tests_coverage",
@@ -30,6 +32,6 @@ def test_with_fft_and_pythran(session):
 
     command = "pdm install -G dev -G test -G fft -G mpi --no-self"
     session.run_always(*command.split(), external=True)
-    session.install(".", "--no-deps")
+    session.install(".", "--no-deps", "-C", "setup-args=-Dnative=true")
 
     session.run("make", "_tests_coverage", external=True)