The maximum AUX area is limited by the page size of the system. Update the documentation to reflect this. Signed-off-by: Shuai Xue <xueshuai@xxxxxxxxxxxxxxxxx> --- tools/perf/Documentation/perf-record.txt | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/tools/perf/Documentation/perf-record.txt b/tools/perf/Documentation/perf-record.txt index 680396c56bd1..dfc322d6f1f1 100644 --- a/tools/perf/Documentation/perf-record.txt +++ b/tools/perf/Documentation/perf-record.txt @@ -292,6 +292,17 @@ OPTIONS Also, by adding a comma, the number of mmap pages for AUX area tracing can be specified. + The maximum AUX area is limited by the maximum physically contiguous + memory allocated from slab/slub. It can be calculated with following + formula: + + PAGE_SIZE << MAX_ORDER + ( ---------------------- ) * PAGE_SIZE + sizeof(page_pointer) + + For example with 4K pages and MAX_ORDER=10 configured, the maximum AUX + area is 2GiB. + -g:: Enables call-graph (stack chain/backtrace) recording for both kernel space and user space. -- 2.39.3
