Re: [PATCH] Use the environment variable PYTHON if defined

From: Raghavendra D Prabhu
Date: Fri Apr 08 2011 - 17:17:24 EST

* On Thu, Mar 31, 2011 at 03:37:40PM +0000, Michael Witten <mfwitten@xxxxxxxxx> wrote:
On Tue, 2011-03-29 17:40:25 -0300, Arnaldo Carvalho de Melo wrote:
Em Tue, Mar 29, 2011 at 02:15:30PM -0500, Michael Witten escreveu:
On Tue, Mar 29, 2011 at 13:15, Raghavendra D Prabhu <rprabhu@xxxxxxxxxxx> wrote:
the patch submitted by Michael seems to be taking care of far
more cases than mine, so that is much better.

One major issue with my current patch is that I opted to stop the
build with an error message even when using the default python command
names; is this undesirable? Is it better to fail silently as before
(via the somewhat cryptic Python.h message), or is it better to force
the user to specify that no python support should be built?

I think that the best course of action is to emit a warning and go, i.e.
we don't have to make it harder for people that don't want $FOO support
to make that clear.

The following patch implements the above requested behavior,
and it is also a bit more robust than the previous patch.

However, consider running this command:

make clean NO_LIBPYTHON=1

and the resulting output:

Python support won't be built
Python support won't be built
rm -f {*.o,*/*.o,*/*/*.o,*/*/*/*.o,libperf.a,perf-archive}
rm -f perf perf-archive perf
rm -f *.spec *.pyc *.pyo */*.pyc */*.pyo common-cmds.h TAGS tags cscope*
make -C Documentation/ clean
make[1]: Entering directory `/usr/src/vanilla/git/linux-2.6/repo/tools/perf/Documentation'
Python support won't be built
make[2]: Entering directory `/usr/src/vanilla/git/linux-2.6/repo/tools/perf'
make[2]: `PERF-VERSION-FILE' is up to date.
make[2]: Leaving directory `/usr/src/vanilla/git/linux-2.6/repo/tools/perf'
rm -f *.xml *.xml+ *.html *.html+ *.1 *.5 *.7
rm -f *.texi *.texi+ *.texi++
rm -f howto-index.txt howto/*.html doc.dep
rm -f technical/api-*.html technical/api-index.txt
rm -f cmds-ancillaryinterrogators.txt cmds-ancillarymanipulators.txt cmds-mainporcelain.txt cmds-plumbinginterrogators.txt cmds-plumbingmanipulators.txt cmds-synchingrepositories.txt cmds-synchelpers.txt cmds-purehelpers.txt cmds-foreignscminterface.txt *.made
make[1]: Leaving directory `/usr/src/vanilla/git/linux-2.6/repo/tools/perf/Documentation'
'/usr/bin/python' util/ clean --build-lib='python' --build-temp='python/temp'
running clean

You'll notice that the line:

Python support won't be built

is repeated thrice. This is annoying, but I think it
could be fixed by restructuring the Makefile to avoid
unnecessary re-processing by GNU Make; as a boon, if
such a restructuring is possible, then it would also
improve the efficiency of running `make'.

Thus, I wouldn't worry about it now.

Michael Witten

Subject: [PATCH] perf tools: Makefile: PYTHON{,_CONFIG} to bandage python3 incompatibility
Date: Thu, 31 Mar 2011 13:52:07 +0000
Currently, python3 is not supported by perf's code; this
can cause the build to fail for systems that have python3
installed as the default python:


The Correct Solution is to write compatibility code so that
python3 works out-of-the-box.

However, users often have an ancillary python2 installed:


Therefore, a quick fix is to allow the user to specify those
ancillary paths as the python binaries that Makefile should
use, thereby avoiding python3 altogether; as an added benefit,
python may be installed in non-standard locations without
the need for updating any PATH variable.

This commit adds the ability to set PYTHON and/or PYTHON_CONFIG
either as environment variables or as make variables on the
command line; the paths may be relative, and usually only
PYTHON is necessary in order for PYTHON_CONFIG to be defined
implicitly. Some rudimentary error checking is performed when
the user explicitly specifies a value for any of these variables.

Thanks to:

Raghavendra D Prabhu <rprabhu@xxxxxxxxxxx>

for motivating this patch.


Message-ID: <e987828e-87ec-4973-95e7-47f10f5d9bab-mfwitten@xxxxxxxxx>

Signed-off-by: Michael Witten <mfwitten@xxxxxxxxx>
tools/perf/Makefile | 77 ++++++++++++++++++++++++++++++-----------
tools/perf/feature-tests.mak | 46 +++++++++++++++++++++++++
2 files changed, 102 insertions(+), 21 deletions(-)

diff --git a/tools/perf/Makefile b/tools/perf/Makefile
index 158c30e..3ef8a28 100644
--- a/tools/perf/Makefile
+++ b/tools/perf/Makefile
@@ -13,6 +13,12 @@ endif

# Define V to have a more verbose compile.

+# Define PYTHON to point to the python binary if the default
+# `python' is not correct; for example: PYTHON=python2
+# Define PYTHON_CONFIG to point to the python-config binary if
+# the default `$(PYTHON)-config' is not correct.
# Define ASCIIDOC8 if you want to format documentation with AsciiDoc 8

# Define DOCBOOK_XSL_172 if you want to format man pages with DocBook XSL v1.72.
@@ -165,8 +171,9 @@ grep-libs = $(filter -l%,$(1))
strip-libs = $(filter-out -l%,$(1))

$(OUTPUT)python/ $(PYRF_OBJS)
- $(QUIET_GEN)python util/ --quiet build_ext --build-lib='$(OUTPUT)python' \
- --build-temp='$(OUTPUT)python/temp'
+ $(QUIET_GEN)'$(PYTHON)' util/ --quiet build_ext \
+ --build-lib='$(OUTPUT)python' \
+ --build-temp='$(OUTPUT)python/temp'

# No Perl scripts right now:

@@ -471,24 +478,53 @@ else

- PYTHON_EMBED_LDOPTS = $(shell python-config --ldflags 2>/dev/null)
- PYTHON_EMBED_CCOPTS = `python-config --cflags 2>/dev/null`
- ifneq ($(call try-cc,$(SOURCE_PYTHON_EMBED),$(FLAGS_PYTHON_EMBED)),y)
- msg := $(warning No Python.h found, install python-dev[el] to have python support in 'perf script' and to build the python bindings)
- else
- LIB_OBJS += $(OUTPUT)util/scripting-engines/trace-event-python.o
- LIB_OBJS += $(OUTPUT)scripts/python/Perf-Trace-Util/Context.o
- endif
+disable-python = $(eval $(call disable-python_code,$(1)))
+define disable-python_code
+ $(if $(1),$(warning No $(1) was found))
+ $(info Python support won't be built)
+override PYTHON := \
+ $(call get-executable-or-default,PYTHON,python)
+ifndef PYTHON
+ $(call disable-python,python interpreter)
+ python-clean=
+ python-clean = '$(PYTHON)' util/ clean \
+ --build-lib='$(OUTPUT)python' \
+ --build-temp='$(OUTPUT)python/temp'
+ $(call disable-python)
+ else
+ override PYTHON_CONFIG := \
+ $(call get-executable-or-default,PYTHON_CONFIG,$(PYTHON)-config)
+ $(call disable-python,python-config tool)
+ else
+ PYTHON_EMBED_LDOPTS = $(shell sh -c "'$(PYTHON_CONFIG)' --ldflags 2>/dev/null")
+ PYTHON_EMBED_CCOPTS = $(shell sh -c "'$(PYTHON_CONFIG)' --cflags 2>/dev/null")
+ ifneq ($(call try-cc,$(SOURCE_PYTHON_EMBED),$(FLAGS_PYTHON_EMBED)),y)
+ $(call disable-python,Python.h)
+ else
+ LIB_OBJS += $(OUTPUT)util/scripting-engines/trace-event-python.o
+ LIB_OBJS += $(OUTPUT)scripts/python/Perf-Trace-Util/Context.o
+ endif
+ endif
+ endif

@@ -829,8 +865,7 @@ clean:
$(RM) *.spec *.pyc *.pyo */*.pyc */*.pyo $(OUTPUT)common-cmds.h TAGS tags cscope*
$(MAKE) -C Documentation/ clean
- @python util/ clean --build-lib='$(OUTPUT)python' \
- --build-temp='$(OUTPUT)python/temp'
+ $(python-clean)

.PHONY: all install clean strip
.PHONY: shell_compatibility_test please_set_SHELL_PATH_to_a_more_modern_shell
diff --git a/tools/perf/feature-tests.mak b/tools/perf/feature-tests.mak
index b041ca6..01e1fb1 100644
--- a/tools/perf/feature-tests.mak
+++ b/tools/perf/feature-tests.mak
@@ -128,3 +128,49 @@ try-cc = $(shell sh -c \
echo "$(1)" | \
$(CC) -x c - $(2) -o "$$TMP" > /dev/null 2>&1 && echo y; \
rm -f "$$TMP"')
+# is-absolute
+# Usage: bool-value = $(call is-absolute,path)
+define is-absolute
+$(shell sh -c "echo '$(1)' | grep ^/")
+# lookup
+# Usage: absolute-executable-path-or-empty = $(call lookup,path)
+define lookup
+$(shell sh -c "command -v '$(1)'")
+# is-executable
+# Usage: bool-value = $(call is-executable,path)
+define is-executable
+$(shell sh -c "test -f '$(1)' -a -x '$(1)' && echo y")
+# get-executable
+# Usage: absolute-executable-path-or-empty = $(call get-executable,path)
+# The goal is to get an absolute path for an executable;
+# the `command -v' is defined by POSIX, but it's not
+# necessarily very portable, so it's only used if
+# relative path resolution is requested, as determined
+# by the presence of a leading `/'.
+define get-executable
+$(if $(1),$(if $(call is-absolute,$(1)),$(if $(call is-executable,$(1)),$(1)),$(call lookup,$(1))))
+# get-supplied-or-default-executable
+# Usage: absolute-executable-path-or-empty = $(call get-executable-or-default,variable,default)
+define get-executable-or-default
+$(if $($(1)),$(call _ge_attempt,$($(1)),$(1)),$(call _ge_attempt,$(2)))
+define _ge_attempt
+$(or $(call get-executable,$(1)),$(call _gea_warn,$(1)),$(call _gea_err,$(2)))
+_gea_warn = $(warning The path '$(1)' is not executable.)
+_gea_err = $(if $(1),$(error Please set '$(1)' appropriately))

Apologies for the delay. I am getting a merge conflict with master now,
it may need to be rebased after the 1b7155f7de119870f0d3fad89f125de2ff6c16be commit.

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