kernel/tools/perf/util/branch.h, branch linux-6.2.y

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

perf callchain: Stitch LBR call stack

2020-04-18T12:05:01Z

In LBR call stack mode, the depth of reconstructed LBR call stack limits to the number of LBR registers. For example, on skylake, the depth of reconstructed LBR call stack is always <= 32. # To display the perf.data header info, please use # --header/--header-only options. # # # Total Lost Samples: 0 # # Samples: 6K of event 'cycles' # Event count (approx.): 6487119731 # # Children Self Command Shared Object Symbol # ........ ........ ............... .................. # ................................ 99.97% 99.97% tchain_edit tchain_edit [.] f43 | --99.64%--f11 f12 f13 f14 f15 f16 f17 f18 f19 f20 f21 f22 f23 f24 f25 f26 f27 f28 f29 f30 f31 f32 f33 f34 f35 f36 f37 f38 f39 f40 f41 f42 f43 For a call stack which is deeper than LBR limit, HW will overwrite the LBR register with oldest branch. Only partial call stacks can be reconstructed. However, the overwritten LBRs may still be retrieved from previous sample. At that moment, HW hasn't overwritten the LBR registers yet. Perf tools can stitch those overwritten LBRs on current call stacks to get a more complete call stack. To determine if LBRs can be stitched, perf tools need to compare current sample with previous sample. - They should have identical LBR records (Same from, to and flags values, and the same physical index of LBR registers). - The searching starts from the base-of-stack of current sample. Once perf determines to stitch the previous LBRs, the corresponding LBR cursor nodes will be copied to 'lists'. The 'lists' is to track the LBR cursor nodes which are going to be stitched. When the stitching is over, the nodes will not be freed immediately. They will be moved to 'free_lists'. Next stitching may reuse the space. Both 'lists' and 'free_lists' will be freed when all samples are processed. Committer notes: Fix the intel-pt.c initialization of the union with 'struct branch_flags', that breaks the build with its unnamed union on older gcc versions. Uninline thread__free_stitch_list(), as it grew big and started dragging includes to thread.h, so move it to thread.c where what it needs in terms of headers are already there. This fixes the build in several systems such as debian:experimental when cross building to the MIPS32 architecture, i.e. in the other cases what was needed was being included by sheer luck. In file included from builtin-sched.c:11: util/thread.h: In function 'thread__free_stitch_list': util/thread.h:169:3: error: implicit declaration of function 'free' [-Werror=implicit-function-declaration] 169 | free(pos); | ^~~~ util/thread.h:169:3: error: incompatible implicit declaration of built-in function 'free' [-Werror] util/thread.h:19:1: note: include '' or provide a declaration of 'free' 18 | #include "callchain.h" +++ |+#include 19 | util/thread.h:174:3: error: incompatible implicit declaration of built-in function 'free' [-Werror] 174 | free(pos); | ^~~~ util/thread.h:174:3: note: include '' or provide a declaration of 'free' Signed-off-by: Kan Liang Reviewed-by: Andi Kleen Acked-by: Jiri Olsa Cc: Adrian Hunter Cc: Alexey Budankov Cc: Mathieu Poirier Cc: Michael Ellerman Cc: Namhyung Kim Cc: Pavel Gerasimov Cc: Peter Zijlstra Cc: Ravi Bangoria Cc: Stephane Eranian Cc: Vitaly Slobodskoy Link: http://lore.kernel.org/lkml/20200319202517.23423-13-kan.liang@linux.intel.com Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Add hw_idx in struct branch_stack

2020-03-10T00:42:53Z

The low level index of raw branch records for the most recent branch can be recorded in a sample with PERF_SAMPLE_BRANCH_HW_INDEX branch_sample_type. Extend struct branch_stack to support it. However, if the PERF_SAMPLE_BRANCH_HW_INDEX is not applied, only nr and entries[] will be output by kernel. The pointer of entries[] could be wrong, since the output format is different with new struct branch_stack. Add a variable no_hw_idx in struct perf_sample to indicate whether the hw_idx is output. Add get_branch_entry() to return corresponding pointer of entries[0]. To make dummy branch sample consistent as new branch sample, add hw_idx in struct dummy_branch_stack for cs-etm and intel-pt. Apply the new struct branch_stack for synthetic events as well. Extend test case sample-parsing to support new struct branch_stack. Committer notes: Renamed get_branch_entries() to perf_sample__branch_entries() to have proper namespacing and pave the way for this to be moved to libperf, eventually. Add 'static' to that inline as it is in a header. Add 'hw_idx' to 'struct dummy_branch_stack' in cs-etm.c to fix the build on arm64. Signed-off-by: Kan Liang Cc: Adrian Hunter Cc: Alexey Budankov Cc: Andi Kleen Cc: Jiri Olsa Cc: Mathieu Poirier Cc: Michael Ellerman Cc: Namhyung Kim Cc: Pavel Gerasimov Cc: Peter Zijlstra Cc: Ravi Bangoria Cc: Stephane Eranian Cc: Vitaly Slobodskoy Link: http://lore.kernel.org/lkml/20200228163011.19358-2-kan.liang@linux.intel.com Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Remove util.h from where it is not needed

2019-09-20T12:19:20Z

Check that it is not needed and remove, fixing up some fallout for places where it was only serving to get something else. Cc: Adrian Hunter Cc: Jiri Olsa Cc: Namhyung Kim Link: https://lkml.kernel.org/n/tip-9h6dg6lsqe2usyqjh5rrues4@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf symbols: Move mem_info and branch_info out of symbol.h

2019-09-01T01:27:48Z

The mem_info struct goes to mem-events.h and branch_info goes to branch.h, where they belong, this way we can remove several headers from symbols.h and trim the include dependency tree more. Cc: Adrian Hunter Cc: Jiri Olsa Cc: Namhyung Kim Link: https://lkml.kernel.org/n/tip-aupw71xnravcsu2xoabfmhpc@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo