ea8d0ed6ea
The new sample type, PERF_SAMPLE_WEIGHT_STRUCT, is an alternative of the PERF_SAMPLE_WEIGHT sample type. Users can apply either the PERF_SAMPLE_WEIGHT sample type or the PERF_SAMPLE_WEIGHT_STRUCT sample type to retrieve the sample weight, but they cannot apply both sample types simultaneously. The new sample type shares the same space as the PERF_SAMPLE_WEIGHT sample type. The lower 32 bits are exactly the same for both sample type. The higher 32 bits may be different for different architecture. Add arch specific arch_evsel__set_sample_weight() to set the new sample type for X86. Only store the lower 32 bits for the sample->weight if the new sample type is applied. In practice, no memory access could last than 4G cycles. No data will be lost. If the kernel doesn't support the new sample type. Fall back to the PERF_SAMPLE_WEIGHT sample type. There is no impact for other architectures. Committer notes: Fixup related to PERF_SAMPLE_CODE_PAGE_SIZE, present in acme/perf/core but not upstream yet. Signed-off-by: Kan Liang <kan.liang@linux.intel.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Jin Yao <yao.jin@linux.intel.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Madhavan Srinivasan <maddy@linux.vnet.ibm.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Link: http://lore.kernel.org/lkml/1612296553-21962-6-git-send-email-kan.liang@linux.intel.com 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.
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.