perf: add perf-inject builtin

Currently, perf 'live mode' writes build-ids at the end of the
session, which isn't actually useful for processing live mode events.

What would be better would be to have the build-ids sent before any of
the samples that reference them, which can be done by processing the
event stream and retrieving the build-ids on the first hit.  Doing
that in perf-record itself, however, is off-limits.

This patch introduces perf-inject, which does the same job while
leaving perf-record untouched.  Normal mode perf still records the
build-ids at the end of the session as it should, but for live mode,
perf-inject can be injected in between the record and report steps
e.g.:

perf record -o - ./hackbench 10 | perf inject -v -b | perf report -v -i -

perf-inject reads a perf-record event stream and repipes it to stdout.
At any point the processing code can inject other events into the
event stream - in this case build-ids (-b option) are read and
injected as needed into the event stream.

Build-ids are just the first user of perf-inject - potentially
anything that needs userspace processing to augment the trace stream
with additional information could make use of this facility.

Cc: Ingo Molnar <mingo@elte.hu>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
LKML-Reference: <1272696080-16435-3-git-send-email-tzanussi@gmail.com>
Signed-off-by: Tom Zanussi <tzanussi@gmail.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index a8dd73ed1581..5d353e70fe26 100644
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -77,7 +77,7 @@ int perf_session__create_kernel_maps(struct perf_session *self)
         return ret;
 }
 
-struct perf_session *perf_session__new(const char *filename, int mode, bool force)
+struct perf_session *perf_session__new(const char *filename, int mode, bool force, bool repipe)
 {
         size_t len = filename ? strlen(filename) + 1 : 0;
         struct perf_session *self = zalloc(sizeof(*self) + len);
@@ -97,6 +97,7 @@ struct perf_session *perf_session__new(const char *filename, int mode, bool forc
         self->cwdlen = 0;
         self->unknown_events = 0;
         self->machines = RB_ROOT;
+        self->repipe = repipe;
         self->ordered_samples.flush_limit = ULLONG_MAX;
         INIT_LIST_HEAD(&self->ordered_samples.samples_head);