Re: [RFC][PATCH 1/9] tracing/events: Add 'signed' field to formatfiles

From: Tom Zanussi
Date: Wed Oct 07 2009 - 01:06:09 EST


On Tue, 2009-10-06 at 21:06 -0400, Steven Rostedt wrote:
> On Tue, 2009-10-06 at 01:09 -0500, Tom Zanussi wrote:
> > The sign info used for filters in the kernel is also useful to
> > applications that process the trace stream. Add it to the format
> > files and make it available to userspace.
> >
> > Signed-off-by: Tom Zanussi <tzanussi@xxxxxxxxx>
> > ---
> > include/trace/ftrace.h | 15 +++++++++------
> > kernel/trace/ring_buffer.c | 15 +++++++++------
> > kernel/trace/trace_events.c | 24 ++++++++++++------------
> > kernel/trace/trace_export.c | 25 ++++++++++++++-----------
> > kernel/trace/trace_syscalls.c | 20 +++++++++++++-------
> > tools/perf/util/trace-event-parse.c | 24 ++++++++++++++++++++++++
> > tools/perf/util/trace-event.h | 1 +
> > 7 files changed, 82 insertions(+), 42 deletions(-)
> >
> > diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h
> > index cc0d966..c9bbcab 100644
> > --- a/include/trace/ftrace.h
> > +++ b/include/trace/ftrace.h
> > @@ -120,9 +120,10 @@
> > #undef __field
> > #define __field(type, item) \
> > ret = trace_seq_printf(s, "\tfield:" #type " " #item ";\t" \
> > - "offset:%u;\tsize:%u;\n", \
> > + "offset:%u;\tsize:%u;\tsigned:%u;\n", \
> > (unsigned int)offsetof(typeof(field), item), \
> > - (unsigned int)sizeof(field.item)); \
> > + (unsigned int)sizeof(field.item), \
> > + (unsigned int)is_signed_type(type)); \
> > if (!ret) \
> > return 0;
>
> I don't mind this change, but it makes me nervous. We really need to
> solidify the output format file. This is adding a new field and will
> already break the parsers in perf and trace_cmd.
>
> Is there anything else that is needed? I really want to make sure that
> we don't need to modify the output of the format files any more.
>

One of the things I had in mind when writing this patchset was to make
sure that what was there already was enough to write something real on
top of. The only thing I found I needed to add was the signed field,
and that was enough at least for the Perl case, where everything can be
mapped into 3 types - signed, unsigned and string.

Other languages might demand more - I haven't looked into it - so I
couldn't say whether anything else is needed, but it would seem to me
that the current combination of type description strings, sizes and
signs for each field should be enough information to allow any field to
be passed into any scripting interpreter. Actually, you could probably
forget about signs and sizes and just manage on type description strings
alone, if you had a typemap that mapped from the C type descriptions to
the types expected by a given interpreter. That might be what some
language implementations would end up doing, but at least for the Perl
implementation, it's much more convenient to have the is_signed field.

Tom

> -- Steve
>
> >
> > @@ -132,19 +133,21 @@
> > #undef __array
> > #define __array(type, item, len) \
> > ret = trace_seq_printf(s, "\tfield:" #type " " #item "[" #len "];\t" \
> > - "offset:%u;\tsize:%u;\n", \
> > + "offset:%u;\tsize:%u;\tsigned:%u;\n", \
> > (unsigned int)offsetof(typeof(field), item), \
> > - (unsigned int)sizeof(field.item)); \
> > + (unsigned int)sizeof(field.item), \
> > + (unsigned int)is_signed_type(type)); \
> > if (!ret) \
> > return 0;
> >
> > #undef __dynamic_array
> > #define __dynamic_array(type, item, len) \
> > ret = trace_seq_printf(s, "\tfield:__data_loc " #type "[] " #item ";\t"\
> > - "offset:%u;\tsize:%u;\n", \
> > + "offset:%u;\tsize:%u;\tsigned:%u;\n", \
> > (unsigned int)offsetof(typeof(field), \
> > __data_loc_##item), \
> > - (unsigned int)sizeof(field.__data_loc_##item)); \
> > + (unsigned int)sizeof(field.__data_loc_##item), \
> > + (unsigned int)is_signed_type(type)); \
> > if (!ret) \
> > return 0;
> >
> > diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
> > index d4ff019..e43c928 100644
> > --- a/kernel/trace/ring_buffer.c
> > +++ b/kernel/trace/ring_buffer.c
> > @@ -397,18 +397,21 @@ int ring_buffer_print_page_header(struct trace_seq *s)
> > int ret;
> >
> > ret = trace_seq_printf(s, "\tfield: u64 timestamp;\t"
> > - "offset:0;\tsize:%u;\n",
> > - (unsigned int)sizeof(field.time_stamp));
> > + "offset:0;\tsize:%u;\tsigned:%u;\n",
> > + (unsigned int)sizeof(field.time_stamp),
> > + (unsigned int)is_signed_type(u64));
> >
> > ret = trace_seq_printf(s, "\tfield: local_t commit;\t"
> > - "offset:%u;\tsize:%u;\n",
> > + "offset:%u;\tsize:%u;\tsigned:%u;\n",
> > (unsigned int)offsetof(typeof(field), commit),
> > - (unsigned int)sizeof(field.commit));
> > + (unsigned int)sizeof(field.commit),
> > + (unsigned int)is_signed_type(long));
> >
> > ret = trace_seq_printf(s, "\tfield: char data;\t"
> > - "offset:%u;\tsize:%u;\n",
> > + "offset:%u;\tsize:%u;\tsigned:%u;\n",
> > (unsigned int)offsetof(typeof(field), data),
> > - (unsigned int)BUF_PAGE_SIZE);
> > + (unsigned int)BUF_PAGE_SIZE,
> > + (unsigned int)is_signed_type(char));
> >
> > return ret;
> > }
> > diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
> > index d128f65..cf3cabf 100644
> > --- a/kernel/trace/trace_events.c
> > +++ b/kernel/trace/trace_events.c
> > @@ -507,7 +507,7 @@ extern char *__bad_type_size(void);
> > #define FIELD(type, name) \
> > sizeof(type) != sizeof(field.name) ? __bad_type_size() : \
> > #type, "common_" #name, offsetof(typeof(field), name), \
> > - sizeof(field.name)
> > + sizeof(field.name), is_signed_type(type)
> >
> > static int trace_write_header(struct trace_seq *s)
> > {
> > @@ -515,17 +515,17 @@ static int trace_write_header(struct trace_seq *s)
> >
> > /* struct trace_entry */
> > return trace_seq_printf(s,
> > - "\tfield:%s %s;\toffset:%zu;\tsize:%zu;\n"
> > - "\tfield:%s %s;\toffset:%zu;\tsize:%zu;\n"
> > - "\tfield:%s %s;\toffset:%zu;\tsize:%zu;\n"
> > - "\tfield:%s %s;\toffset:%zu;\tsize:%zu;\n"
> > - "\tfield:%s %s;\toffset:%zu;\tsize:%zu;\n"
> > - "\n",
> > - FIELD(unsigned short, type),
> > - FIELD(unsigned char, flags),
> > - FIELD(unsigned char, preempt_count),
> > - FIELD(int, pid),
> > - FIELD(int, lock_depth));
> > + "\tfield:%s %s;\toffset:%zu;\tsize:%zu;\tsigned:%u;\n"
> > + "\tfield:%s %s;\toffset:%zu;\tsize:%zu;\tsigned:%u;\n"
> > + "\tfield:%s %s;\toffset:%zu;\tsize:%zu;\tsigned:%u;\n"
> > + "\tfield:%s %s;\toffset:%zu;\tsize:%zu;\tsigned:%u;\n"
> > + "\tfield:%s %s;\toffset:%zu;\tsize:%zu;\tsigned:%u;\n"
> > + "\n",
> > + FIELD(unsigned short, type),
> > + FIELD(unsigned char, flags),
> > + FIELD(unsigned char, preempt_count),
> > + FIELD(int, pid),
> > + FIELD(int, lock_depth));
> > }
> >
> > static ssize_t
> > diff --git a/kernel/trace/trace_export.c b/kernel/trace/trace_export.c
> > index 9753fcc..31da218 100644
> > --- a/kernel/trace/trace_export.c
> > +++ b/kernel/trace/trace_export.c
> > @@ -66,44 +66,47 @@ static void __used ____ftrace_check_##name(void) \
> > #undef __field
> > #define __field(type, item) \
> > ret = trace_seq_printf(s, "\tfield:" #type " " #item ";\t" \
> > - "offset:%zu;\tsize:%zu;\n", \
> > + "offset:%zu;\tsize:%zu;\tsigned:%u;\n", \
> > offsetof(typeof(field), item), \
> > - sizeof(field.item)); \
> > + sizeof(field.item), is_signed_type(type)); \
> > if (!ret) \
> > return 0;
> >
> > #undef __field_desc
> > #define __field_desc(type, container, item) \
> > ret = trace_seq_printf(s, "\tfield:" #type " " #item ";\t" \
> > - "offset:%zu;\tsize:%zu;\n", \
> > + "offset:%zu;\tsize:%zu;\tsigned:%u;\n", \
> > offsetof(typeof(field), container.item), \
> > - sizeof(field.container.item)); \
> > + sizeof(field.container.item), \
> > + is_signed_type(type)); \
> > if (!ret) \
> > return 0;
> >
> > #undef __array
> > #define __array(type, item, len) \
> > ret = trace_seq_printf(s, "\tfield:" #type " " #item "[" #len "];\t" \
> > - "offset:%zu;\tsize:%zu;\n", \
> > - offsetof(typeof(field), item), \
> > - sizeof(field.item)); \
> > + "offset:%zu;\tsize:%zu;\tsigned:%u;\n", \
> > + offsetof(typeof(field), item), \
> > + sizeof(field.item), is_signed_type(type)); \
> > if (!ret) \
> > return 0;
> >
> > #undef __array_desc
> > #define __array_desc(type, container, item, len) \
> > ret = trace_seq_printf(s, "\tfield:" #type " " #item "[" #len "];\t" \
> > - "offset:%zu;\tsize:%zu;\n", \
> > + "offset:%zu;\tsize:%zu;\tsigned:%u;\n", \
> > offsetof(typeof(field), container.item), \
> > - sizeof(field.container.item)); \
> > + sizeof(field.container.item), \
> > + is_signed_type(type)); \
> > if (!ret) \
> > return 0;
> >
> > #undef __dynamic_array
> > #define __dynamic_array(type, item) \
> > ret = trace_seq_printf(s, "\tfield:" #type " " #item ";\t" \
> > - "offset:%zu;\tsize:0;\n", \
> > - offsetof(typeof(field), item)); \
> > + "offset:%zu;\tsize:0;\tsigned:%u;\n", \
> > + offsetof(typeof(field), item), \
> > + is_signed_type(type)); \
> > if (!ret) \
> > return 0;
> >
> > diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
> > index 527e17e..d99abc4 100644
> > --- a/kernel/trace/trace_syscalls.c
> > +++ b/kernel/trace/trace_syscalls.c
> > @@ -103,7 +103,8 @@ extern char *__bad_type_size(void);
> > #define SYSCALL_FIELD(type, name) \
> > sizeof(type) != sizeof(trace.name) ? \
> > __bad_type_size() : \
> > - #type, #name, offsetof(typeof(trace), name), sizeof(trace.name)
> > + #type, #name, offsetof(typeof(trace), name), \
> > + sizeof(trace.name), is_signed_type(type)
> >
> > int syscall_enter_format(struct ftrace_event_call *call, struct trace_seq *s)
> > {
> > @@ -120,7 +121,8 @@ int syscall_enter_format(struct ftrace_event_call *call, struct trace_seq *s)
> > if (!entry)
> > return 0;
> >
> > - ret = trace_seq_printf(s, "\tfield:%s %s;\toffset:%zu;\tsize:%zu;\n",
> > + ret = trace_seq_printf(s, "\tfield:%s %s;\toffset:%zu;\tsize:%zu;"
> > + "\tsigned:%u;\n",
> > SYSCALL_FIELD(int, nr));
> > if (!ret)
> > return 0;
> > @@ -130,8 +132,10 @@ int syscall_enter_format(struct ftrace_event_call *call, struct trace_seq *s)
> > entry->args[i]);
> > if (!ret)
> > return 0;
> > - ret = trace_seq_printf(s, "\toffset:%d;\tsize:%zu;\n", offset,
> > - sizeof(unsigned long));
> > + ret = trace_seq_printf(s, "\toffset:%d;\tsize:%zu;"
> > + "\tsigned:%u;\n", offset,
> > + sizeof(unsigned long),
> > + is_signed_type(unsigned long));
> > if (!ret)
> > return 0;
> > offset += sizeof(unsigned long);
> > @@ -163,8 +167,10 @@ int syscall_exit_format(struct ftrace_event_call *call, struct trace_seq *s)
> > struct syscall_trace_exit trace;
> >
> > ret = trace_seq_printf(s,
> > - "\tfield:%s %s;\toffset:%zu;\tsize:%zu;\n"
> > - "\tfield:%s %s;\toffset:%zu;\tsize:%zu;\n",
> > + "\tfield:%s %s;\toffset:%zu;\tsize:%zu;"
> > + "\tsigned:%u;\n"
> > + "\tfield:%s %s;\toffset:%zu;\tsize:%zu;"
> > + "\tsigned:%u;\n",
> > SYSCALL_FIELD(int, nr),
> > SYSCALL_FIELD(long, ret));
> > if (!ret)
> > @@ -212,7 +218,7 @@ int syscall_exit_define_fields(struct ftrace_event_call *call)
> > if (ret)
> > return ret;
> >
> > - ret = trace_define_field(call, SYSCALL_FIELD(long, ret), 0,
> > + ret = trace_define_field(call, SYSCALL_FIELD(long, ret),
> > FILTER_OTHER);
> >
> > return ret;
> > diff --git a/tools/perf/util/trace-event-parse.c b/tools/perf/util/trace-event-parse.c
> > index 55b41b9..be8412d 100644
> > --- a/tools/perf/util/trace-event-parse.c
> > +++ b/tools/perf/util/trace-event-parse.c
> > @@ -897,6 +897,21 @@ static int event_read_fields(struct event *event, struct format_field **fields)
> > if (read_expected(EVENT_OP, (char *)";") < 0)
> > goto fail_expect;
> >
> > + if (read_expected(EVENT_ITEM, (char *)"signed") < 0)
> > + goto fail_expect;
> > +
> > + if (read_expected(EVENT_OP, (char *)":") < 0)
> > + goto fail_expect;
> > +
> > + if (read_expect_type(EVENT_ITEM, &token))
> > + goto fail;
> > + if (strtoul(token, NULL, 0))
> > + field->flags |= FIELD_IS_SIGNED;
> > + free_token(token);
> > +
> > + if (read_expected(EVENT_OP, (char *)";") < 0)
> > + goto fail_expect;
> > +
> > if (read_expect_type(EVENT_NEWLINE, &token) < 0)
> > goto fail;
> > free_token(token);
> > @@ -2845,6 +2860,15 @@ static void parse_header_field(char *type,
> > free_token(token);
> > if (read_expected(EVENT_OP, (char *)";") < 0)
> > return;
> > + if (read_expected(EVENT_ITEM, (char *)"signed") < 0)
> > + return;
> > + if (read_expected(EVENT_OP, (char *)":") < 0)
> > + return;
> > + if (read_expect_type(EVENT_ITEM, &token) < 0)
> > + return;
> > + free_token(token);
> > + if (read_expected(EVENT_OP, (char *)";") < 0)
> > + return;
> > if (read_expect_type(EVENT_NEWLINE, &token) < 0)
> > return;
> > free_token(token);
> > diff --git a/tools/perf/util/trace-event.h b/tools/perf/util/trace-event.h
> > index 162c3e6..00b440d 100644
> > --- a/tools/perf/util/trace-event.h
> > +++ b/tools/perf/util/trace-event.h
> > @@ -26,6 +26,7 @@ enum {
> > enum format_flags {
> > FIELD_IS_ARRAY = 1,
> > FIELD_IS_POINTER = 2,
> > + FIELD_IS_SIGNED = 4,
> > };
> >
> > struct format_field {
>

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