tools build feature: Check if libaio is available

This will be used by 'perf record' to speed up reading the perf ring
buffer.

Committer testing:

$ make -C tools/perf O=/tmp/build/perf
make: Entering directory '/home/acme/git/perf/tools/perf'
BUILD: Doing 'make -j8' parallel build

Auto-detecting system features:
... dwarf: [ on ]
... dwarf_getlocations: [ on ]
... glibc: [ on ]
... gtk2: [ OFF ]
... libaudit: [ OFF ]
... libbfd: [ OFF ]
... libelf: [ on ]
... libnuma: [ OFF ]
... numa_num_possible_cpus: [ OFF ]
... libperl: [ OFF ]
... libpython: [ OFF ]
... libslang: [ on ]
... libcrypto: [ on ]
... libunwind: [ on ]
... libdw-dwarf-unwind: [ on ]
... zlib: [ on ]
... lzma: [ on ]
... get_cpuid: [ on ]
... bpf: [ on ]
... libaio: [ on ]

$ ls -la /tmp/build/perf/feature/test-libaio.*
-rwxrwxr-x. 1 acme acme 18296 Nov 26 08:49 /tmp/build/perf/feature/test-libaio.bin
-rw-rw-r--. 1 acme acme 1165 Nov 26 08:49 /tmp/build/perf/feature/test-libaio.d
-rw-rw-r--. 1 acme acme 0 Nov 26 08:49 /tmp/build/perf/feature/test-libaio.make.output
$
$ grep -i aio /tmp/build/perf/FEATURE-DUMP
feature-libaio=1
$

Signed-off-by: Alexey Budankov <[e-mail]>
Tested-by: Arnaldo Carvalho de Melo <[e-mail]>
Reviewed-by: Jiri Olsa <[e-mail]>
Acked-by: Namhyung Kim <[e-mail]>
Cc: Alexander Shishkin <[e-mail]>
Cc: Andi Kleen <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Link: http://lkml.kernel.org/r/[e-mail]
[ split from a larger patch ]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/build/Makefile.feature

···
         sched_getcpu			\
         sdt				\
         setns				\
-        libopencsd
+        libopencsd			\
+        libaio
 
 # FEATURE_TESTS_BASIC + FEATURE_TESTS_EXTRA is the complete list
 # of all feature tests
···
          zlib                   \
          lzma                   \
          get_cpuid              \
-         bpf
+         bpf			\
+         libaio
 
 # Set FEATURE_CHECK_(C|LD)FLAGS-all for all FEATURE_TESTS features.
 # If in the future we need per-feature checks/flags for features not

tools/build/feature/Makefile

···
          test-libopencsd.bin			\
          test-clang.bin				\
          test-llvm.bin				\
-         test-llvm-version.bin
+         test-llvm-version.bin			\
+         test-libaio.bin
 
 FILES := $(addprefix $(OUTPUT),$(FILES))
 
···
 		> $(@:.bin=.make.output) 2>&1
 
 -include $(OUTPUT)*.d
+
+$(OUTPUT)test-libaio.bin:
+	$(BUILD) -lrt
 
 ###############################
 

tools/build/feature/test-all.c

···
 # include "test-libopencsd.c"
 #undef main
 
+#define main main_test_libaio
+# include "test-libaio.c"
+#undef main
+
 int main(int argc, char *argv[])
 {
 	main_test_libpython();
···
 	main_test_sdt();
 	main_test_setns();
 	main_test_libopencsd();
+	main_test_libaio();
 
 	return 0;
 }

tools/build/feature/test-libaio.c

···
+// SPDX-License-Identifier: GPL-2.0
+#include <aio.h>
+
+int main(void)
+{
+	struct aiocb aiocb;
+
+	aiocb.aio_fildes  = 0;
+	aiocb.aio_offset  = 0;
+	aiocb.aio_buf     = 0;
+	aiocb.aio_nbytes  = 0;
+	aiocb.aio_reqprio = 0;
+	aiocb.aio_sigevent.sigev_notify = 1 /*SIGEV_NONE*/;
+
+	return (int)aio_return(&aiocb);
+}

tools/perf/Makefile.config

···
   CFLAGS += -DHAVE_GLIBC_SUPPORT
 endif
 
+ifeq ($(feature-libaio), 1)
+  ifndef NO_AIO
+    CFLAGS += -DHAVE_AIO_SUPPORT
+  endif
+endif
+
 ifdef NO_DWARF
   NO_LIBDW_DWARF_UNWIND := 1
 endif

tools/perf/Makefile.perf

···
 # Define LIBCLANGLLVM if you DO want builtin clang and llvm support.
 # When selected, pass LLVM_CONFIG=/path/to/llvm-config to `make' if
 # llvm-config is not in $PATH.
-
+#
 # Define NO_CORESIGHT if you do not want support for CoreSight trace decoding.
+#
+# Define NO_AIO if you do not want support of Posix AIO based trace
+# streaming for record mode. Currently Posix AIO trace streaming is
+# supported only when linking with glibc.
+#
 
 # As per kernel Makefile, avoid funny character set dependencies
 unexport LC_ALL