* [PATCH] perf build: Do not duplicate CFLAGS in Python extension builds
@ 2026-06-10 11:23 Jens Remus
2026-06-10 13:38 ` James Clark
0 siblings, 1 reply; 4+ messages in thread
From: Jens Remus @ 2026-06-10 11:23 UTC (permalink / raw)
To: linux-s390, Peter Zijlstra, Ingo Molnar, Arnaldo Carvalho de Melo,
Namhyung Kim, Mark Rutland, Alexander Shishkin, Jiri Olsa,
Ian Rogers, Adrian Hunter, James Clark, linux-perf-users,
linux-kernel
Cc: Jens Remus, Jan Polensky, Thomas Richter, Hendrik Brueckner,
Heiko Carstens
setuptools already uses CFLAGS. Passing CFLAGS with additional flags as
extra compile arguments causes CFLAGS to effectively get passed twice:
$ make -C tools/perf V=1 JOBS=1
...
building 'perf' extension
gcc [CFLAGS] -fPIC -Iutil/include -I/usr/include/python3.14 \
-c /root/linux/tools/perf/util/python.c \
-o python_ext_build/tmp/root/linux/tools/perf/util/python.o \
[CFLAGS] \
-fno-strict-aliasing -Wno-write-strings -Wno-unused-parameter \
-Wno-redundant-decls -Wno-cast-function-type \
-Wno-declaration-after-statement
Signed-off-by: Jens Remus <jremus@linux.ibm.com>
---
Notes (jremus):
This patch applies on top of the perf-tools-next tree:
git://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools-next.git master
Note that my "[PATCH v2] perf build: Respect V=1 for Python extension
builds" [1] needs to be applied to actually observe the Python extension
build command and output with V=1.
[1]: https://lore.kernel.org/all/20260608160613.3153795-1-jremus@linux.ibm.com/
tools/perf/util/setup.py | 13 ++++++-------
1 file changed, 6 insertions(+), 7 deletions(-)
diff --git a/tools/perf/util/setup.py b/tools/perf/util/setup.py
index b65b1792ca05..a0ce76624a23 100644
--- a/tools/perf/util/setup.py
+++ b/tools/perf/util/setup.py
@@ -74,18 +74,17 @@ class install_lib(_install_lib):
self.build_dir = build_lib
-cflags = getenv('CFLAGS', '').split()
# switch off several checks (need to be at the end of cflags list)
-cflags += ['-fno-strict-aliasing', '-Wno-write-strings', '-Wno-unused-parameter', '-Wno-redundant-decls' ]
+extra_cflags = ['-fno-strict-aliasing', '-Wno-write-strings', '-Wno-unused-parameter', '-Wno-redundant-decls' ]
if cc_is_clang:
- cflags += ["-Wno-unused-command-line-argument" ]
+ extra_cflags += ["-Wno-unused-command-line-argument" ]
if clang_has_option("-Wno-cast-function-type-mismatch"):
- cflags += ["-Wno-cast-function-type-mismatch" ]
+ extra_cflags += ["-Wno-cast-function-type-mismatch" ]
else:
- cflags += ['-Wno-cast-function-type' ]
+ extra_cflags += ['-Wno-cast-function-type' ]
# The python headers have mixed code with declarations (decls after asserts, for instance)
-cflags += [ "-Wno-declaration-after-statement" ]
+extra_cflags += [ "-Wno-declaration-after-statement" ]
src_perf = f'{srctree}/tools/perf'
build_lib = getenv('PYTHON_EXTBUILD_LIB')
@@ -94,7 +93,7 @@ build_tmp = getenv('PYTHON_EXTBUILD_TMP')
perf = Extension('perf',
sources = [ src_perf + '/util/python.c' ],
include_dirs = ['util/include'],
- extra_compile_args = cflags,
+ extra_compile_args = extra_cflags,
)
setup(name='perf',
--
2.53.0
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH] perf build: Do not duplicate CFLAGS in Python extension builds
2026-06-10 11:23 [PATCH] perf build: Do not duplicate CFLAGS in Python extension builds Jens Remus
@ 2026-06-10 13:38 ` James Clark
2026-06-10 20:02 ` Arnaldo Carvalho de Melo
0 siblings, 1 reply; 4+ messages in thread
From: James Clark @ 2026-06-10 13:38 UTC (permalink / raw)
To: Jens Remus
Cc: Jan Polensky, Thomas Richter, Hendrik Brueckner, Heiko Carstens,
linux-s390, Peter Zijlstra, Ingo Molnar, Arnaldo Carvalho de Melo,
Namhyung Kim, Mark Rutland, Alexander Shishkin, Jiri Olsa,
Ian Rogers, Adrian Hunter, linux-perf-users, linux-kernel
On 10/06/2026 12:23 pm, Jens Remus wrote:
> setuptools already uses CFLAGS. Passing CFLAGS with additional flags as
> extra compile arguments causes CFLAGS to effectively get passed twice:
>
> $ make -C tools/perf V=1 JOBS=1
> ...
> building 'perf' extension
> gcc [CFLAGS] -fPIC -Iutil/include -I/usr/include/python3.14 \
> -c /root/linux/tools/perf/util/python.c \
> -o python_ext_build/tmp/root/linux/tools/perf/util/python.o \
> [CFLAGS] \
> -fno-strict-aliasing -Wno-write-strings -Wno-unused-parameter \
> -Wno-redundant-decls -Wno-cast-function-type \
> -Wno-declaration-after-statement
>
> Signed-off-by: Jens Remus <jremus@linux.ibm.com>
Reviewed-by: James Clark <james.clark@linaro.org>
> ---
>
> Notes (jremus):
> This patch applies on top of the perf-tools-next tree:
>
> git://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools-next.git master
>
> Note that my "[PATCH v2] perf build: Respect V=1 for Python extension
> builds" [1] needs to be applied to actually observe the Python extension
> build command and output with V=1.
>
> [1]: https://lore.kernel.org/all/20260608160613.3153795-1-jremus@linux.ibm.com/
>
> tools/perf/util/setup.py | 13 ++++++-------
> 1 file changed, 6 insertions(+), 7 deletions(-)
>
> diff --git a/tools/perf/util/setup.py b/tools/perf/util/setup.py
> index b65b1792ca05..a0ce76624a23 100644
> --- a/tools/perf/util/setup.py
> +++ b/tools/perf/util/setup.py
> @@ -74,18 +74,17 @@ class install_lib(_install_lib):
> self.build_dir = build_lib
>
>
> -cflags = getenv('CFLAGS', '').split()
> # switch off several checks (need to be at the end of cflags list)
> -cflags += ['-fno-strict-aliasing', '-Wno-write-strings', '-Wno-unused-parameter', '-Wno-redundant-decls' ]
> +extra_cflags = ['-fno-strict-aliasing', '-Wno-write-strings', '-Wno-unused-parameter', '-Wno-redundant-decls' ]
> if cc_is_clang:
> - cflags += ["-Wno-unused-command-line-argument" ]
> + extra_cflags += ["-Wno-unused-command-line-argument" ]
> if clang_has_option("-Wno-cast-function-type-mismatch"):
> - cflags += ["-Wno-cast-function-type-mismatch" ]
> + extra_cflags += ["-Wno-cast-function-type-mismatch" ]
> else:
> - cflags += ['-Wno-cast-function-type' ]
> + extra_cflags += ['-Wno-cast-function-type' ]
>
> # The python headers have mixed code with declarations (decls after asserts, for instance)
> -cflags += [ "-Wno-declaration-after-statement" ]
> +extra_cflags += [ "-Wno-declaration-after-statement" ]
>
> src_perf = f'{srctree}/tools/perf'
> build_lib = getenv('PYTHON_EXTBUILD_LIB')
> @@ -94,7 +93,7 @@ build_tmp = getenv('PYTHON_EXTBUILD_TMP')
> perf = Extension('perf',
> sources = [ src_perf + '/util/python.c' ],
> include_dirs = ['util/include'],
> - extra_compile_args = cflags,
> + extra_compile_args = extra_cflags,
> )
>
> setup(name='perf',
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] perf build: Do not duplicate CFLAGS in Python extension builds
2026-06-10 13:38 ` James Clark
@ 2026-06-10 20:02 ` Arnaldo Carvalho de Melo
0 siblings, 0 replies; 4+ messages in thread
From: Arnaldo Carvalho de Melo @ 2026-06-10 20:02 UTC (permalink / raw)
To: James Clark
Cc: Jens Remus, Jan Polensky, Thomas Richter, Hendrik Brueckner,
Heiko Carstens, linux-s390, Peter Zijlstra, Ingo Molnar,
Namhyung Kim, Mark Rutland, Alexander Shishkin, Jiri Olsa,
Ian Rogers, Adrian Hunter, linux-perf-users, linux-kernel
On Wed, Jun 10, 2026 at 02:38:24PM +0100, James Clark wrote:
>
>
> On 10/06/2026 12:23 pm, Jens Remus wrote:
> > setuptools already uses CFLAGS. Passing CFLAGS with additional flags as
> > extra compile arguments causes CFLAGS to effectively get passed twice:
> >
> > $ make -C tools/perf V=1 JOBS=1
> > ...
> > building 'perf' extension
> > gcc [CFLAGS] -fPIC -Iutil/include -I/usr/include/python3.14 \
> > -c /root/linux/tools/perf/util/python.c \
> > -o python_ext_build/tmp/root/linux/tools/perf/util/python.o \
> > [CFLAGS] \
> > -fno-strict-aliasing -Wno-write-strings -Wno-unused-parameter \
> > -Wno-redundant-decls -Wno-cast-function-type \
> > -Wno-declaration-after-statement
> >
> > Signed-off-by: Jens Remus <jremus@linux.ibm.com>
>
> Reviewed-by: James Clark <james.clark@linaro.org>
Thanks, applied to perf-tools-next, for v7.2.
- Arnaldo
^ permalink raw reply [flat|nested] 4+ messages in thread
* [PATCH] perf build: Do not duplicate CFLAGS in Python extension builds
@ 2026-06-10 11:13 Jens Remus
0 siblings, 0 replies; 4+ messages in thread
From: Jens Remus @ 2026-06-10 11:13 UTC (permalink / raw)
To: Peter Zijlstra, Ingo Molnar, Arnaldo Carvalho de Melo,
Namhyung Kim, Mark Rutland, Alexander Shishkin, Jiri Olsa,
Ian Rogers, Adrian Hunter, James Clark, linux-perf-users,
linux-kernel
Cc: Jens Remus, Jan Polensky, Thomas Richter, Heiko Carstens
setuptools already uses CFLAGS. Passing CFLAGS with additional flags as
extra compile arguments causes CFLAGS to effectively get passed twice:
$ make -C tools/perf V=1 JOBS=1
...
building 'perf' extension
gcc [CFLAGS] -fPIC -Iutil/include -I/usr/include/python3.14 \
-c /root/linux/tools/perf/util/python.c \
-o python_ext_build/tmp/root/linux/tools/perf/util/python.o \
[CFLAGS] \
-fno-strict-aliasing -Wno-write-strings -Wno-unused-parameter \
-Wno-redundant-decls -Wno-cast-function-type \
-Wno-declaration-after-statement
Signed-off-by: Jens Remus <jremus@linux.ibm.com>
---
Notes (jremus):
This patch applies on top of the perf-tools-next tree:
git://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools-next.git master
Note that my "[PATCH v2] perf build: Respect V=1 for Python extension
builds" [1] needs to be applied to actually observe the Python extension
build command and output with V=1.
[1]: https://lore.kernel.org/all/20260608160613.3153795-1-jremus@linux.ibm.com/
tools/perf/util/setup.py | 13 ++++++-------
1 file changed, 6 insertions(+), 7 deletions(-)
diff --git a/tools/perf/util/setup.py b/tools/perf/util/setup.py
index b65b1792ca05..a0ce76624a23 100644
--- a/tools/perf/util/setup.py
+++ b/tools/perf/util/setup.py
@@ -74,18 +74,17 @@ class install_lib(_install_lib):
self.build_dir = build_lib
-cflags = getenv('CFLAGS', '').split()
# switch off several checks (need to be at the end of cflags list)
-cflags += ['-fno-strict-aliasing', '-Wno-write-strings', '-Wno-unused-parameter', '-Wno-redundant-decls' ]
+extra_cflags = ['-fno-strict-aliasing', '-Wno-write-strings', '-Wno-unused-parameter', '-Wno-redundant-decls' ]
if cc_is_clang:
- cflags += ["-Wno-unused-command-line-argument" ]
+ extra_cflags += ["-Wno-unused-command-line-argument" ]
if clang_has_option("-Wno-cast-function-type-mismatch"):
- cflags += ["-Wno-cast-function-type-mismatch" ]
+ extra_cflags += ["-Wno-cast-function-type-mismatch" ]
else:
- cflags += ['-Wno-cast-function-type' ]
+ extra_cflags += ['-Wno-cast-function-type' ]
# The python headers have mixed code with declarations (decls after asserts, for instance)
-cflags += [ "-Wno-declaration-after-statement" ]
+extra_cflags += [ "-Wno-declaration-after-statement" ]
src_perf = f'{srctree}/tools/perf'
build_lib = getenv('PYTHON_EXTBUILD_LIB')
@@ -94,7 +93,7 @@ build_tmp = getenv('PYTHON_EXTBUILD_TMP')
perf = Extension('perf',
sources = [ src_perf + '/util/python.c' ],
include_dirs = ['util/include'],
- extra_compile_args = cflags,
+ extra_compile_args = extra_cflags,
)
setup(name='perf',
--
2.53.0
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2026-06-10 11:23 [PATCH] perf build: Do not duplicate CFLAGS in Python extension builds Jens Remus
2026-06-10 13:38 ` James Clark
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