From f8dd2d5ff953bc498d682ae8022439c940a7d5c4 Mon Sep 17 00:00:00 2001 From: Wang Nan Date: Fri, 26 Feb 2016 09:31:57 +0000 Subject: [PATCH] perf data: Explicitly set byte order for integer types MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit After babeltrace commit 5cec03e402aa ("ir: copy variants and sequences when setting a field path"), 'perf data convert' gets incorrect result if there's bpf output data. For example: # perf data convert --to-ctf ./out.ctf # babeltrace ./out.ctf [10:44:31.186045346] (+?.?????????) evt: { cpu_id = 0 }, { perf_ip = 0xFFFFFFFF810E7DD1, perf_tid = 23819, perf_pid = 23819, perf_id = 518, raw_len = 3, raw_data = [ [0] = 0xC028E32F, [1] = 0x815D0100, [2] = 0x1000000 ] } [10:44:31.286101003] (+0.100055657) evt: { cpu_id = 0 }, { perf_ip = 0xFFFFFFFF8105B609, perf_tid = 23819, perf_pid = 23819, perf_id = 518, raw_len = 3, raw_data = [ [0] = 0x35D9F1EB, [1] = 0x15D81, [2] = 0x2 ] } The expected result of the first sample should be: raw_data = [ [0] = 0x2FE328C0, [1] = 0x15D81, [2] = 0x1 ] } however, 'perf data convert' output big endian value to resuling CTF file. The reason is a internal change (or a bug?) of babeltrace. Before this patch, at the first add_bpf_output_values(), byte order of all integer type is uncertain (is 0, neither 1234 (le) nor 4321 (be)). It would be fixed by: perf_evlist__deliver_sample -> process_sample_event -> ctf_stream ... ->bt_ctf_trace_add_stream_class ->bt_ctf_field_type_structure_set_byte_order ->bt_ctf_field_type_integer_set_byte_order during creating the stream. However, the babeltrace commit mentioned above duplicates types in sequence to prevent potential conflict in following call stack and link the newly allocated type into the 'raw_data' sequence: perf_evlist__deliver_sample -> process_sample_event -> ctf_stream ... -> bt_ctf_trace_add_stream_class -> bt_ctf_stream_class_resolve_types ... -> bt_ctf_field_type_sequence_copy ->bt_ctf_field_type_integer_copy This happens before byte order setting, so only the newly allocated type is initialized, the byte order of original type perf choose to create the first raw_data is still uncertain. Byte order in CTF output is not related to byte order in perf.data. Setting it to anything other than BT_CTF_BYTE_ORDER_NATIVE solves this problem (only BT_CTF_BYTE_ORDER_NATIVE needs to be fixed). To reduce behavior changing, set byte order according to compiling options. Signed-off-by: Wang Nan Cc: Jeremie Galarneau Cc: Alexei Starovoitov Cc: Brendan Gregg Cc: Jiri Olsa Cc: Jérémie Galarneau Cc: Li Zefan Cc: Masami Hiramatsu Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Zefan Li Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1456479154-136027-10-git-send-email-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/data-convert-bt.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/tools/perf/util/data-convert-bt.c b/tools/perf/util/data-convert-bt.c index 1f608a6e2c14..811af89ce0bb 100644 --- a/tools/perf/util/data-convert-bt.c +++ b/tools/perf/util/data-convert-bt.c @@ -1080,6 +1080,12 @@ static struct bt_ctf_field_type *create_int_type(int size, bool sign, bool hex) bt_ctf_field_type_integer_set_base(type, BT_CTF_INTEGER_BASE_HEXADECIMAL)) goto err; +#if __BYTE_ORDER == __BIG_ENDIAN + bt_ctf_field_type_set_byte_order(type, BT_CTF_BYTE_ORDER_BIG_ENDIAN); +#else + bt_ctf_field_type_set_byte_order(type, BT_CTF_BYTE_ORDER_LITTLE_ENDIAN); +#endif + pr2("Created type: INTEGER %d-bit %ssigned %s\n", size, sign ? "un" : "", hex ? "hex" : ""); return type; -- 2.20.1