[PATCH] perf inject: Clarify build-id options a little bit

[Namhyung Kim <namhyung@kernel.org>]

Update the documentation of --build-id and --buildid-all options to
clarify the difference between them.  The former requires full sample
processing to find which DSOs are actually used.  While the latter simply
injects every DSO's build-id from MMAP{,2} records, skipping SAMPLEs.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
---
 tools/perf/Documentation/perf-inject.txt | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/tools/perf/Documentation/perf-inject.txt b/tools/perf/Documentation/perf-inject.txt
index 70e2ac3cc91a..c972032f4ca0 100644
--- a/tools/perf/Documentation/perf-inject.txt
+++ b/tools/perf/Documentation/perf-inject.txt
@@ -25,10 +25,12 @@ OPTIONS
 -------
 -b::
 --build-ids::
-        Inject build-ids into the output stream
+	Inject build-ids of DSOs hit by samples into the output stream.
+	This means it needs to process all SAMPLE records to find the DSOs.
 
 --buildid-all::
-	Inject build-ids of all DSOs into the output stream
+	Inject build-ids of all DSOs into the output stream regardless of hits
+	and skip SAMPLE processing.
 
 --known-build-ids=::
 	Override build-ids to inject using these comma-separated pairs of
-- 
2.37.2.789.g6183377224-goog