fabd37b837
So far if we use 'perf record -g' this will make symbol_conf.use_callchain 'true' and logic will assume that all events have callchains enabled, but ever since we added the possibility of setting up callchains for some events (e.g.: -e cycles/call-graph=dwarf/) while not for others, we limit usage scenarios by looking at that symbol_conf.use_callchain global boolean, we better look at each event attributes. On the road to that we need to look if a hist_entry has callchains, that is, to go from hist_entry->hists to the evsel that contains it, to then look at evsel->sample_type for PERF_SAMPLE_CALLCHAIN. The next step is to add a symbol_conf.ignore_callchains global, to use in the places where what we really want to know is if callchains should be ignored, even if present. Then -g will mean just to select a callchain mode to be applied to all events not explicitely setting some other callchain mode, i.e. a default callchain mode, and --no-call-graph will set symbol_conf.ignore_callchains with that clear intention. That too will at some point become a per evsel thing, that tools can set for all or just a few of its evsels. Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: David Ahern <dsahern@gmail.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Wang Nan <wangnan0@huawei.com> Link: https://lkml.kernel.org/n/tip-0sas5cm4dsw2obn75g7ruz69@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.