6ade6c6460
Show the branch speculation info if provided by the branch recording hardware feature. This can be useful for optimizing code further. The speculation info is appended to the end of the list of fields so any existing tools that use "/" as a delimiter for access fields via an index remain unaffected. Also show "-" instead of "N/A" when speculation info is unavailable because "/" is used as the field separator. E.g. $ perf record -j any,u,save_type ./test_branch $ perf script --fields brstacksym Before: [...] check_match+0x60/strcmp+0x0/P/-/-/0/CALL do_lookup_x+0x3c5/check_match+0x0/P/-/-/0/CALL [...] After: [...] check_match+0x60/strcmp+0x0/P/-/-/0/CALL/NON_SPEC_CORRECT_PATH do_lookup_x+0x3c5/check_match+0x0/P/-/-/0/CALL/NON_SPEC_CORRECT_PATH [...] The bitfield swapping scheme used duing sample parsing has changed because of the addition of new branch flags, namely "spec", "new_type" and "priv". Earlier, these were all part of the "reserved" field but now, each of these fields get swapped separately. Change the expected flag values accordingly for the test to pass. E.g. $ perf test -v 27 Before: 27: Sample parsing : --- start --- test child forked, pid 61979 parsing failed for sample_type 0x800 test child finished with -1 ---- end ---- Sample parsing: FAILED! After: 27: Sample parsing : --- start --- test child forked, pid 63293 test child finished with 0 ---- end ---- Sample parsing: Ok Signed-off-by: Sandipan Das <sandipan.das@amd.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Ananth Narayan <ananth.narayan@amd.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Ian Rogers <irogers@google.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: James Clark <james.clark@arm.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Kajol Jain <kjain@linux.ibm.com> Cc: Madhavan Srinivasan <maddy@linux.ibm.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ravi Bangoria <ravi.bangoria@amd.com> Cc: Santosh Shukla <santosh.shukla@amd.com> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Thomas Richter <tmricht@linux.ibm.com> Cc: x86@kernel.org Link: https://lore.kernel.org/r/56e272583552526e999ba0b536ac009ae3613966.1675333809.git.sandipan.das@amd.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.