tools build feature: Check if eventfd() is available (11c6cbe7) · Commits · 戴 / test

A new 'perf bench epoll' will use this, and to disable it for older systems, add a feature test for this API. This is just a simple program that if successfully compiled, means that the feature is present, at least at the library level, in a build that sets the output directory to /tmp/build/perf (using O=/tmp/build/perf), we end up with: $ ls -la /tmp/build/perf/feature/test-eventfd* -rwxrwxr-x. 1 acme acme 8176 Nov 21 15:58 /tmp/build/perf/feature/test-eventfd.bin -rw-rw-r--. 1 acme acme 588 Nov 21 15:58 /tmp/build/perf/feature/test-eventfd.d -rw-rw-r--. 1 acme acme 0 Nov 21 15:58 /tmp/build/perf/feature/test-eventfd.make.output $ ldd /tmp/build/perf/feature/test-eventfd.bin linux-vdso.so.1 (0x00007fff3bf3f000) libc.so.6 => /lib64/libc.so.6 (0x00007fa984061000) /lib64/ld-linux-x86-64.so.2 (0x00007fa984417000) $ grep eventfd -A 2 -B 2 /tmp/build/perf/FEATURE-DUMP feature-dwarf=1 feature-dwarf_getlocations=1 feature-eventfd=1 feature-fortify-source=1 feature-sync-compare-and-swap=1 $ The main thing here is that in the end we'll have -DHAVE_EVENTFD in CFLAGS, and then the 'perf bench' entry needing that API can be selectively pruned. Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: David Ahern <dsahern@gmail.com> Cc: Davidlohr Bueso <dbueso@suse.de> Cc: Jason Baron <jbaron@akamai.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Wang Nan <wangnan0@huawei.com> Link: https://lkml.kernel.org/n/tip-wkeldwob7dpx6jvtuzl8164k@git.kernel.org Signed-off-by:

Arnaldo Carvalho de Melo <acme@redhat.com>

tools/build/Makefile.feature

+1 −0

Original line number	Diff line number	Diff line
		@@ -31,6 +31,7 @@ FEATURE_TESTS_BASIC := \
		backtrace \
		dwarf \
		dwarf_getlocations \
		eventfd \
		fortify-source \
		sync-compare-and-swap \
		get_current_dir_name \

tools/build/feature/Makefile

+4 −0

Original line number	Diff line number	Diff line
		@@ -5,6 +5,7 @@ FILES= \
		test-bionic.bin \
		test-dwarf.bin \
		test-dwarf_getlocations.bin \
		test-eventfd.bin \
		test-fortify-source.bin \
		test-sync-compare-and-swap.bin \
		test-get_current_dir_name.bin \
		@@ -102,6 +103,9 @@ $(OUTPUT)test-bionic.bin:
		$(OUTPUT)test-libelf.bin:
		$(BUILD) -lelf

		$(OUTPUT)test-eventfd.bin:
		$(BUILD)

		$(OUTPUT)test-get_current_dir_name.bin:
		$(BUILD)

tools/build/feature/test-all.c

+5 −0

Original line number	Diff line number	Diff line
		@@ -50,6 +50,10 @@
		# include "test-dwarf_getlocations.c"
		#undef main

		#define main main_test_eventfd
		# include "test-eventfd.c"
		#undef main

		#define main main_test_libelf_getphdrnum
		# include "test-libelf-getphdrnum.c"
		#undef main
		@@ -182,6 +186,7 @@ int main(int argc, char *argv[])
		main_test_glibc();
		main_test_dwarf();
		main_test_dwarf_getlocations();
		main_test_eventfd();
		main_test_libelf_getphdrnum();
		main_test_libelf_gelf_getnote();
		main_test_libelf_getshdrstrndx();

tools/build/feature/test-eventfd.c

0 → 100644

+9 −0

Original line number	Diff line number	Diff line
		// SPDX-License-Identifier: GPL-2.0
		// Copyright (C) 2018, Red Hat Inc, Arnaldo Carvalho de Melo <acme@redhat.com>

		#include <sys/eventfd.h>

		int main(void)
		{
		return eventfd(0, EFD_NONBLOCK);
		}

tools/perf/Makefile.config

+4 −1

Original line number	Diff line number	Diff line
		@@ -299,11 +299,14 @@ ifndef NO_BIONIC
		endif
		endif

		ifeq ($(feature-eventfd), 1)
		CFLAGS += -DHAVE_EVENTFD
		endif

		ifeq ($(feature-get_current_dir_name), 1)
		CFLAGS += -DHAVE_GET_CURRENT_DIR_NAME
		endif


		ifdef NO_LIBELF
		NO_DWARF := 1
		NO_DEMANGLE := 1

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