kernel/tools/perf/util/branch.h, branch linux-rolling-stable

perf script: Add not taken event for branch stack

2025-03-05T17:13:19Z

The branch stack has an existed field for printing mispredict, extend the field for printing events and add support not-taken event. Reviewed-by: Ian Rogers Reviewed-by: James Clark Signed-off-by: Leo Yan Link: https://lore.kernel.org/r/20250304111240.3378214-6-leo.yan@arm.com Signed-off-by: Namhyung Kim

perf annotate: Save branch counters for each block

2024-08-14T13:20:40Z

When annotating a basic block, it's useful to display the occurrences of other events in the block. The branch counter feature is only available for newer Intel platforms. So a dedicated option to display the branch counters is not introduced. Reuse the existing --total-cycles option, which triggers the annotation of a basic block and displays the cycle-related annotation. When the branch counters information is available, the branch counters are automatically appended after all the cycle-related annotation. Accounting the branch counters as well when accounting the cycles in hist__account_cycles(). In 'struct annotated_branch', introduce a br_cntr array to save the accumulation of each branch counter. In a sample, all the branch counters for a branch are saved in a u64 space. Because the saturation of a branch counter is small, e.g., for Intel Sierra Forest, the saturation is only 3. Add ANNOTATION__BR_CNTR_SATURATED_FLAG to indicate if a branch counter once saturated. That can be used to indicate a potential event lost because of the saturation. Reviewed-by: Andi Kleen Signed-off-by: Kan Liang Acked-by: Namhyung Kim Cc: Adrian Hunter Cc: Ian Rogers Cc: Ingo Molnar Cc: Peter Zijlstra Cc: Stephane Eranian Link: https://lore.kernel.org/r/20240813160208.2493643-5-kan.liang@linux.intel.com Signed-off-by: Arnaldo Carvalho de Melo

perf callchain: Make display use of branch_type_stat const

2023-10-25T20:38:50Z

Display code doesn't modify the branch_type_stat so switch uses to const. This is done to aid refactoring struct callchain_list where current the branch_type_stat is embedded even if not used. Signed-off-by: Ian Rogers Cc: K Prateek Nayak Cc: Ravi Bangoria Cc: Sandipan Das Cc: Anshuman Khandual Cc: German Gomez Cc: James Clark Cc: Nick Terrell Cc: Sean Christopherson Cc: Changbin Du Cc: liuwenyu Cc: Yang Jihong Cc: Masami Hiramatsu Cc: Miguel Ojeda Cc: Song Liu Cc: Leo Yan Cc: Kajol Jain Cc: Andi Kleen Cc: Kan Liang Cc: Athira Rajeev Cc: Yanteng Si Cc: Liam Howlett Cc: Paolo Bonzini Link: https://lore.kernel.org/r/20231024222353.3024098-9-irogers@google.com Signed-off-by: Namhyung Kim

perf script: Show branch speculation info

2023-02-02T20:18:31Z

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 Tested-by: Arnaldo Carvalho de Melo Cc: Alexander Shishkin Cc: Ananth Narayan Cc: Borislav Petkov Cc: Dave Hansen Cc: Ian Rogers Cc: Ingo Molnar Cc: James Clark Cc: Jiri Olsa Cc: Kajol Jain Cc: Madhavan Srinivasan Cc: Mark Rutland Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Ravi Bangoria Cc: Santosh Shukla Cc: Stephane Eranian Cc: Thomas Gleixner Cc: Thomas Richter Cc: x86@kernel.org Link: https://lore.kernel.org/r/56e272583552526e999ba0b536ac009ae3613966.1675333809.git.sandipan.das@amd.com Signed-off-by: Arnaldo Carvalho de Melo

perf branch: Fix interpretation of branch records

2022-12-05T12:29:14Z

Commit 93315e46b000fc80 ("perf/core: Add speculation info to branch entries") added a new field in between type and new_type. Perf has its own copy of this struct so update it to match the kernel side. This doesn't currently cause any issues because new_type is only used by the Arm BRBE driver which isn't merged yet. Committer notes: Is this really an ABI? How are we supposed to deal with old perf.data files with new tools and vice versa? :-\ Fixes: 93315e46b000fc80 ("perf/core: Add speculation info to branch entries") Reviewed-by: Anshuman Khandual Signed-off-by: James Clark Acked-by: Namhyung Kim Cc: Alexander Shishkin Cc: Ingo Molnar Cc: Jiri Olsa Cc: Mark Rutland Cc: Peter Zijlstra Cc: Sandipan Das Link: https://lore.kernel.org/r/20221130165158.517385-1-james.clark@arm.com Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Move 'struct perf_sample' to a separate header file to disentangle headers

2022-10-31T14:06:41Z

Some places were including event.h just to get 'struct perf_sample', move it to a separate place so that we speed up a bit the build. Signed-off-by: Arnaldo Carvalho de Melo

perf branch: Remove some needless headers, add a needed one

2022-10-31T14:06:34Z

map_symbol.h is needed because we have structs that contains 'struct addr_map_symbol', so add it, remove the others. Signed-off-by: Arnaldo Carvalho de Melo

perf branch: Add branch privilege information request flag

2022-10-04T11:55:20Z

This updates the perf tools with branch privilege information request flag i.e PERF_SAMPLE_BRANCH_PRIV_SAVE that has been added earlier in the kernel. This also updates 'perf record' documentation, branch_modes[], and generic branch privilege level enumeration as added earlier in the kernel. Signed-off-by: Anshuman Khandual Cc: Alexander Shishkin Cc: Catalin Marinas Cc: Ingo Molnar Cc: James Clark Cc: Jiri Olsa Cc: Mark Rutland Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Robin Murphy Cc: Suzuki Poulouse Cc: Thomas Gleixner Cc: Will Deacon Cc: linux-arm-kernel@lists.infradead.org Link: https://lore.kernel.org/r/20220824044822.70230-8-anshuman.khandual@arm.com Signed-off-by: Arnaldo Carvalho de Melo

perf branch: Extend branch type classification

2022-10-04T11:55:20Z

This updates the perf tool with generic branch type classification with new ABI extender place holder i.e PERF_BR_EXTEND_ABI, the new 4 bit branch type field i.e perf_branch_entry.new_type, new generic page fault related branch types and some arch specific branch types as added earlier in the kernel. Committer note: Add an extra entry to the branch_type_name array to cope with PERF_BR_EXTEND_ABI, to address build warnings on some compiler/systems, like: 75 8.89 ubuntu:20.04-x-powerpc64el : FAIL gcc version 10.3.0 (Ubuntu 10.3.0-1ubuntu1~20.04) inlined from 'branch_type_stat_display' at util/branch.c:152:4: /usr/powerpc64le-linux-gnu/include/bits/stdio2.h:100:10: error: '%8s' directive argument is null [-Werror=format-overflow=] 100 | return __fprintf_chk (__stream, __USE_FORTIFY_LEVEL - 1, __fmt, | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 101 | __va_arg_pack ()); | ~~~~~~~~~~~~~~~~~ Signed-off-by: Anshuman Khandual Cc: Alexander Shishkin Cc: Catalin Marinas Cc: Ingo Molnar Cc: James Clark Cc: Jiri Olsa Cc: Mark Rutland Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Robin Murphy Cc: Stephen Rothwell Cc: Suzuki Poulouse Cc: Thomas Gleixner Cc: Will Deacon Cc: linux-arm-kernel@lists.infradead.org Link: https://lore.kernel.org/r/20220824044822.70230-7-anshuman.khandual@arm.com Signed-off-by: Arnaldo Carvalho de Melo

perf branch: Replace zero-length array with flexible-array

2020-05-28T13:03:27Z

The current codebase makes use of the zero-length array language extension to the C90 standard, but the preferred mechanism to declare variable-length types such as these ones is a flexible array member[1][2], introduced in C99: struct foo { int stuff; struct boo array[]; }; By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last in the structure, which will help us prevent some kind of undefined behavior bugs from being inadvertently introduced[3] to the codebase from now on. Also, notice that, dynamic memory allocations won't be affected by this change: "Flexible array members have incomplete type, and so the sizeof operator may not be applied. As a quirk of the original implementation of zero-length arrays, sizeof evaluates to zero."[1] sizeof(flexible-array-member) triggers a warning because flexible array members have incomplete type[1]. There are some instances of code in which the sizeof operator is being incorrectly/erroneously applied to zero-length arrays and the result is zero. Such instances may be hiding some bugs. So, this work (flexible-array member conversions) will also help to get completely rid of those sorts of issues. This issue was found with the help of Coccinelle and audited _manually_. [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html [2] https://github.com/KSPP/linux/issues/21 [3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour") Signed-off-by: Gustavo A. R. Silva Cc: Alexander Shishkin Cc: Gustavo A. R. Silva Cc: Jiri Olsa Cc: Mark Rutland Cc: Namhyung Kim Cc: Peter Zijlstra Link: http://lore.kernel.org/lkml/20200520191613.GA26869@embeddedor Signed-off-by: Arnaldo Carvalho de Melo