Re: [PATCH] perf docs: Refine the description for the buffer size

From: James Clark
Date: Mon Aug 12 2024 - 05:12:07 EST




On 10/08/2024 5:15 pm, Leo Yan wrote:
Current description for the AUX trace buffer size is misleading. When a
user specifies the option '-m,512M', it represents a size value in bytes
(512MiB) but not 512M pages (512M x 4KiB regard to a page of 4KiB).

Make the document clear that the normal buffer and the AUX tracing
buffer share the same semantics.

Signed-off-by: Leo Yan <leo.yan@xxxxxxx>
---
tools/perf/Documentation/perf-record.txt | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/tools/perf/Documentation/perf-record.txt b/tools/perf/Documentation/perf-record.txt
index 41e36b4dc765..242223240a08 100644
--- a/tools/perf/Documentation/perf-record.txt
+++ b/tools/perf/Documentation/perf-record.txt
@@ -273,10 +273,11 @@ OPTIONS
-m::
--mmap-pages=::
Number of mmap data pages (must be a power of two) or size
- specification with appended unit character - B/K/M/G. The
- size is rounded up to have nearest pages power of two value.
- Also, by adding a comma, the number of mmap pages for AUX
- area tracing can be specified.
+ specification in bytes with appended unit character - B/K/M/G.
+ The size is rounded up to the nearest power-of-two page value.
+ By adding a comma, an additional parameter with the same
+ semantics used for the normal mmap areas can be specified for
+ AUX tracing area.
-g::
Enables call-graph (stack chain/backtrace) recording for both

The same text is repeated on a few tools, probably makes sense to update them all at the same time.

With that change:

Reviewed-by: James Clark <james.clark@xxxxxxxxxx>