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Date: Thu, 12 Dec 2013 15:42:23 +0200
From: Adrian Hunter <adrian.hunter@...el.com>
To: Arnaldo Carvalho de Melo <acme@...stprotocols.net>
CC: Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
Peter Zijlstra <a.p.zijlstra@...llo.nl>,
Ingo Molnar <mingo@...hat.com>, linux-kernel@...r.kernel.org,
David Ahern <dsahern@...il.com>,
Frederic Weisbecker <fweisbec@...il.com>,
Jiri Olsa <jolsa@...hat.com>, Mike Galbraith <efault@....de>,
Namhyung Kim <namhyung@...il.com>,
Paul Mackerras <paulus@...ba.org>,
Stephane Eranian <eranian@...gle.com>,
Andi Kleen <ak@...ux.intel.com>
Subject: Re: [PATCH v0 21/71] perf tools: Add feature test for __sync_val_compare_and_swap
On 11/12/13 21:24, Arnaldo Carvalho de Melo wrote:
> Em Wed, Dec 11, 2013 at 02:36:33PM +0200, Alexander Shishkin escreveu:
>> From: Adrian Hunter <adrian.hunter@...el.com>
>>
>> Add a feature test for __sync_val_compare_and_swap()
>> and __sync_bool_compare_and_swap()
>
> This makes the global feature tests to be rebuilt all the time, i.e. no
> more caching on a relatively recent system:
>
> [acme@...andy linux]$ gcc -v
> Using built-in specs.
> COLLECT_GCC=/usr/bin/gcc
> COLLECT_LTO_WRAPPER=/usr/libexec/gcc/x86_64-redhat-linux/4.7.2/lto-wrapper
> Target: x86_64-redhat-linux
> Configured with: ../configure --prefix=/usr --mandir=/usr/share/man
> --infodir=/usr/share/info
> --with-bugurl=http://bugzilla.redhat.com/bugzilla --enable-bootstrap
> --enable-shared --enable-threads=posix --enable-checking=release
> --disable-build-with-cxx --disable-build-poststage1-with-cxx
> --with-system-zlib --enable-__cxa_atexit --disable-libunwind-exceptions
> --enable-gnu-unique-object --enable-linker-build-id
> --with-linker-hash-style=gnu
> --enable-languages=c,c++,objc,obj-c++,java,fortran,ada,go,lto
> --enable-plugin --enable-initfini-array --enable-java-awt=gtk
> --disable-dssi --with-java-home=/usr/lib/jvm/java-1.5.0-gcj-1.5.0.0/jre
> --enable-libgcj-multifile --enable-java-maintainer-mode
> --with-ecj-jar=/usr/share/java/eclipse-ecj.jar
> --disable-libjava-multilib --with-ppl --with-cloog --with-tune=generic
> --with-arch_32=i686 --build=x86_64-redhat-linux
> Thread model: posix
> gcc version 4.7.2 20121109 (Red Hat 4.7.2-8) (GCC)
> [acme@...andy linux]$o
>
> [acme@...andy linux]$ cat /etc/fedora-release
> Fedora release 18 (Spherical Cow)
>
> Can you provide more info about these gcc builtins and what is the
> minimum system where this test will succeed?
The first reference in the gcc manuals is in gcc version 4.1.2
http://gcc.gnu.org/onlinedocs/gcc-4.1.2/gcc/
However I am not sure what will happen on all architectures. The gcc manual
says:
Not all operations are supported by all target processors. If a
particular operation cannot be implemented on the target processor,
a warning is generated and a call an external function is
generated. The external function carries the same name as the
built-in version, with an additional suffix ‘_n’ where n is the
size of the data type.
>
> In this system it works, as I can see:
>
> ... sync-compare-and-swap: [ on ]
>
> [acme@...andy linux]$ time make O=/tmp/build/perf -C tools/perf/
> install-bin
> make: Entering directory `/home/acme/git/linux/tools/perf'
> BUILD: Doing 'make -j8' parallel build
>
> Auto-detecting system features:
> ... backtrace: [ on ]
> ... dwarf: [ on ]
> ... fortify-source: [ on ]
> ... sync-compare-and-swap: [ on ]
> ... glibc: [ on ]
> ... gtk2: [ on ]
> ... gtk2-infobar: [ on ]
> ... libaudit: [ on ]
> ... libbfd: [ on ]
> ... libelf: [ on ]
> ... libelf-getphdrnum: [ on ]
> ... libelf-mmap: [ on ]
> ... libnuma: [ on ]
> ... libperl: [ on ]
> ... libpython: [ on ]
> ... libpython-version: [ on ]
> ... libslang: [ on ]
> ... libunwind: [ on ]
> ... on-exit: [ on ]
> ... stackprotector-all: [ on ]
> ... timerfd: [ on ]
>
> GEN perf-archive
>
> Please check the recent changes from Jean Pihet, I think he had similar
> problems, i.e. caching stopped working.
The problem is argc and argv must be passed to
main_test_sync_compare_and_swap(). Will be fixed next
version.
>
> - Arnaldo
>
>
>> Signed-off-by: Adrian Hunter <adrian.hunter@...el.com>
>> ---
>> tools/perf/config/Makefile | 5 +++++
>> tools/perf/config/feature-checks/Makefile | 4 ++++
>> tools/perf/config/feature-checks/test-all.c | 5 +++++
>> .../config/feature-checks/test-sync-compare-and-swap.c | 14 ++++++++++++++
>> 4 files changed, 28 insertions(+)
>> create mode 100644 tools/perf/config/feature-checks/test-sync-compare-and-swap.c
>>
>> diff --git a/tools/perf/config/Makefile b/tools/perf/config/Makefile
>> index bae1072..43a2879 100644
>> --- a/tools/perf/config/Makefile
>> +++ b/tools/perf/config/Makefile
>> @@ -126,6 +126,7 @@ CORE_FEATURE_TESTS = \
>> backtrace \
>> dwarf \
>> fortify-source \
>> + sync-compare-and-swap \
>> glibc \
>> gtk2 \
>> gtk2-infobar \
>> @@ -234,6 +235,10 @@ CFLAGS += -I$(LIB_INCLUDE)
>>
>> CFLAGS += -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -D_GNU_SOURCE
>>
>> +ifeq ($(feature-sync-compare-and-swap), 1)
>> + CFLAGS += -DHAVE_SYNC_COMPARE_AND_SWAP_SUPPORT
>> +endif
>> +
>> ifndef NO_BIONIC
>> $(call feature_check,bionic)
>> ifeq ($(feature-bionic), 1)
>> diff --git a/tools/perf/config/feature-checks/Makefile b/tools/perf/config/feature-checks/Makefile
>> index b8bb749..b4b7bb2 100644
>> --- a/tools/perf/config/feature-checks/Makefile
>> +++ b/tools/perf/config/feature-checks/Makefile
>> @@ -5,6 +5,7 @@ FILES= \
>> test-bionic \
>> test-dwarf \
>> test-fortify-source \
>> + test-sync-compare-and-swap \
>> test-glibc \
>> test-gtk2 \
>> test-gtk2-infobar \
>> @@ -140,6 +141,9 @@ test-backtrace:
>> test-timerfd:
>> $(BUILD)
>>
>> +test-sync-compare-and-swap:
>> + $(BUILD)
>> +
>> -include *.d
>>
>> ###############################
>> diff --git a/tools/perf/config/feature-checks/test-all.c b/tools/perf/config/feature-checks/test-all.c
>> index 9b8a544..5cfec18 100644
>> --- a/tools/perf/config/feature-checks/test-all.c
>> +++ b/tools/perf/config/feature-checks/test-all.c
>> @@ -89,6 +89,10 @@
>> # include "test-stackprotector-all.c"
>> #undef main
>>
>> +#define main main_test_sync_compare_and_swap
>> +# include "test-sync-compare-and-swap.c"
>> +#undef main
>> +
>> int main(int argc, char *argv[])
>> {
>> main_test_libpython();
>> @@ -111,6 +115,7 @@ int main(int argc, char *argv[])
>> main_test_libnuma();
>> main_test_timerfd();
>> main_test_stackprotector_all();
>> + main_test_sync_compare_and_swap();
>>
>> return 0;
>> }
>> diff --git a/tools/perf/config/feature-checks/test-sync-compare-and-swap.c b/tools/perf/config/feature-checks/test-sync-compare-and-swap.c
>> new file mode 100644
>> index 0000000..c34d4ca
>> --- /dev/null
>> +++ b/tools/perf/config/feature-checks/test-sync-compare-and-swap.c
>> @@ -0,0 +1,14 @@
>> +#include <stdint.h>
>> +
>> +volatile uint64_t x;
>> +
>> +int main(int argc, char *argv[])
>> +{
>> + uint64_t old, new = argc;
>> +
>> + argv = argv;
>> + do {
>> + old = __sync_val_compare_and_swap(&x, 0, 0);
>> + } while (!__sync_bool_compare_and_swap(&x, old, new));
>> + return old == new;
>> +}
>> --
>> 1.8.5.1
>
>
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