libperf cpumap: Replace usage of perf_cpu_map__new(NULL) with perf_cpu_map__new_online_cpus()

Passing NULL to perf_cpu_map__new() performs
perf_cpu_map__new_online_cpus(), just directly call
perf_cpu_map__new_online_cpus() to be more intention revealing.

Reviewed-by: James Clark <james.clark@arm.com>
Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexandre Ghiti <alexghiti@rivosinc.com>
Cc: Andrew Jones <ajones@ventanamicro.com>
Cc: André Almeida <andrealmeid@igalia.com>
Cc: Athira Jajeev <atrajeev@linux.vnet.ibm.com>
Cc: Atish Patra <atishp@rivosinc.com>
Cc: Changbin Du <changbin.du@huawei.com>
Cc: Darren Hart <dvhart@infradead.org>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Garry <john.g.garry@oracle.com>
Cc: K Prateek Nayak <kprateek.nayak@amd.com>
Cc: Kajol Jain <kjain@linux.ibm.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Paran Lee <p4ranlee@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Bangoria <ravi.bangoria@amd.com>
Cc: Sandipan Das <sandipan.das@amd.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Steinar H. Gunderson <sesse@google.com>
Cc: Suzuki Poulouse <suzuki.poulose@arm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will@kernel.org>
Cc: Yang Jihong <yangjihong1@huawei.com>
Cc: Yang Li <yang.lee@linux.alibaba.com>
Cc: Yanteng Si <siyanteng@loongson.cn>
Cc: bpf@vger.kernel.org
Cc: coresight@lists.linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Link: https://lore.kernel.org/r/20231129060211.1890454-5-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf bpf_counter: Fix a few memory leaks

Memory leaks were detected by clang-tidy.

Signed-off-by: Ian Rogers <irogers@google.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Ravi Bangoria <ravi.bangoria@amd.com>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Yang Jihong <yangjihong1@huawei.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: llvm@lists.linux.dev
Cc: Ming Wang <wangming01@loongson.cn>
Cc: Tom Rix <trix@redhat.com>
Cc: bpf@vger.kernel.org
Link: https://lore.kernel.org/r/20231009183920.200859-20-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>

perf bperf: Avoid use after free via unrelated 'struct evsel' anonymous union field

If bperf (perf tools that use BPF skels) sets evsel->leader_skel or
evsel->follower_skel then it appears that evsel->bpf_skel is set and can
trigger the following use-after-free:

==13575==ERROR: AddressSanitizer: heap-use-after-free on address 0x60c000014080 at pc 0x55684b939880 bp 0x7ffdfcf30d70 sp 0x7ffdfcf30d68
READ of size 8 at 0x60c000014080 thread T0
#0 0x55684b93987f in sample_filter_bpf__destroy tools/perf/bpf_skel/sample_filter.skel.h:44:11
#1 0x55684b93987f in perf_bpf_filter__destroy tools/perf/util/bpf-filter.c:155:2
#2 0x55684b98f71e in evsel__exit tools/perf/util/evsel.c:1521:2
#3 0x55684b98a352 in evsel__delete tools/perf/util/evsel.c:1547:2
#4 0x55684b981918 in evlist__purge tools/perf/util/evlist.c:148:3
#5 0x55684b981918 in evlist__delete tools/perf/util/evlist.c:169:2
#6 0x55684b887d60 in cmd_stat tools/perf/builtin-stat.c:2598:2
..
0x60c000014080 is located 0 bytes inside of 128-byte region [0x60c000014080,0x60c000014100)
freed by thread T0 here:
#0 0x55684b780e86 in free compiler-rt/lib/asan/asan_malloc_linux.cpp:52:3
#1 0x55684b9462da in bperf_cgroup_bpf__destroy tools/perf/bpf_skel/bperf_cgroup.skel.h:61:2
#2 0x55684b9462da in bperf_cgrp__destroy tools/perf/util/bpf_counter_cgroup.c:282:2
#3 0x55684b944c75 in bpf_counter__destroy tools/perf/util/bpf_counter.c:819:2
#4 0x55684b98f716 in evsel__exit tools/perf/util/evsel.c:1520:2
#5 0x55684b98a352 in evsel__delete tools/perf/util/evsel.c:1547:2
#6 0x55684b981918 in evlist__purge tools/perf/util/evlist.c:148:3
#7 0x55684b981918 in evlist__delete tools/perf/util/evlist.c:169:2
#8 0x55684b887d60 in cmd_stat tools/perf/builtin-stat.c:2598:2
...
previously allocated by thread T0 here:
#0 0x55684b781338 in calloc compiler-rt/lib/asan/asan_malloc_linux.cpp:77:3
#1 0x55684b944e25 in bperf_cgroup_bpf__open_opts tools/perf/bpf_skel/bperf_cgroup.skel.h:73:35
#2 0x55684b944e25 in bperf_cgroup_bpf__open tools/perf/bpf_skel/bperf_cgroup.skel.h:97:9
#3 0x55684b944e25 in bperf_load_program tools/perf/util/bpf_counter_cgroup.c:55:9
#4 0x55684b944e25 in bperf_cgrp__load tools/perf/util/bpf_counter_cgroup.c:178:23
#5 0x55684b889289 in __run_perf_stat tools/perf/builtin-stat.c:713:7
#6 0x55684b889289 in run_perf_stat tools/perf/builtin-stat.c:949:8
#7 0x55684b888029 in cmd_stat tools/perf/builtin-stat.c:2537:12

Resolve by clearing 'evsel->bpf_skel' as part of bpf_counter__destroy().

Suggested-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: bpf@vger.kernel.org
Link: http://lore.kernel.org/lkml/20230411051718.267228-1-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf bpf_counter: Use public cpumap accessors

Avoid the use of internal apis via the cpumap accessor functions.

Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexey Bayduraev <alexey.v.bayduraev@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: André Almeida <andrealmeid@collabora.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Darren Hart <dvhart@infradead.org>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Dmitriy Vyukov <dvyukov@google.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: German Gomez <german.gomez@arm.com>
Cc: Hao Luo <haoluo@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@arm.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Garry <john.g.garry@oracle.com>
Cc: Kajol Jain <kjain@linux.ibm.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Miaoqian Lin <linmq006@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Riccardo Mancini <rickyman7@gmail.com>
Cc: Shunsuke Nakamura <nakamura.shun@fujitsu.com>
Cc: Song Liu <song@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Stephen Brennan <stephen.s.brennan@oracle.com>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Thomas Richter <tmricht@linux.ibm.com>
Cc: Yury Norov <yury.norov@gmail.com>
Link: https://lore.kernel.org/r/20230320033810.980165-2-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf record: Add BPF event filter support

Use --filter option to set BPF filter for generic events other than the
tracepoints or Intel PT. The BPF program will check the sample data and
filter according to the expression.

For example, the below is the typical perf record for frequency mode.
The sample period started from 1 and increased gradually.

$ sudo ./perf record -e cycles true
$ sudo ./perf script
perf-exec 2272336 546683.916875: 1 cycles: ffffffff828499b8 perf_event_exec+0x298 ([kernel.kallsyms])
perf-exec 2272336 546683.916892: 1 cycles: ffffffff828499b8 perf_event_exec+0x298 ([kernel.kallsyms])
perf-exec 2272336 546683.916899: 3 cycles: ffffffff828499b8 perf_event_exec+0x298 ([kernel.kallsyms])
perf-exec 2272336 546683.916905: 17 cycles: ffffffff828499b8 perf_event_exec+0x298 ([kernel.kallsyms])
perf-exec 2272336 546683.916911: 100 cycles: ffffffff828499b8 perf_event_exec+0x298 ([kernel.kallsyms])
perf-exec 2272336 546683.916917: 589 cycles: ffffffff828499b8 perf_event_exec+0x298 ([kernel.kallsyms])
perf-exec 2272336 546683.916924: 3470 cycles: ffffffff828499b8 perf_event_exec+0x298 ([kernel.kallsyms])
perf-exec 2272336 546683.916930: 20465 cycles: ffffffff828499b8 perf_event_exec+0x298 ([kernel.kallsyms])
true 2272336 546683.916940: 119873 cycles: ffffffff8283afdd perf_iterate_ctx+0x2d ([kernel.kallsyms])
true 2272336 546683.917003: 461349 cycles: ffffffff82892517 vma_interval_tree_insert+0x37 ([kernel.kallsyms])
true 2272336 546683.917237: 635778 cycles: ffffffff82a11400 security_mmap_file+0x20 ([kernel.kallsyms])

When you add a BPF filter to get samples having periods greater than 1000,
the output would look like below:

$ sudo ./perf record -e cycles --filter 'period > 1000' true
$ sudo ./perf script
perf-exec 2273949 546850.708501: 5029 cycles: ffffffff826f9e25 finish_wait+0x5 ([kernel.kallsyms])
perf-exec 2273949 546850.708508: 32409 cycles: ffffffff826f9e25 finish_wait+0x5 ([kernel.kallsyms])
perf-exec 2273949 546850.708526: 143369 cycles: ffffffff82b4cdbf xas_start+0x5f ([kernel.kallsyms])
perf-exec 2273949 546850.708600: 372650 cycles: ffffffff8286b8f7 __pagevec_lru_add+0x117 ([kernel.kallsyms])
perf-exec 2273949 546850.708791: 482953 cycles: ffffffff829190de __mod_memcg_lruvec_state+0x4e ([kernel.kallsyms])
true 2273949 546850.709036: 501985 cycles: ffffffff828add7c tlb_gather_mmu+0x4c ([kernel.kallsyms])
true 2273949 546850.709292: 503065 cycles: 7f2446d97c03 _dl_map_object_deps+0x973 (/usr/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2)

Committer notes:

Add stubs for perf_bpf_filter__prepare() and perf_bpf_filter__destroy()
to tools/perf/util/python.c to keep it building.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Hao Luo <haoluo@google.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: James Clark <james.clark@arm.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Bangoria <ravi.bangoria@amd.com>
Cc: Song Liu <song@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: bpf@vger.kernel.org
Link: https://lore.kernel.org/r/20230314234237.3008956-2-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf bpf: Remove pre libbpf 1.0 conditional logic

Tests are no longer applicable as libbpf 1.0 can be assumed.

Signed-off-by: Ian Rogers <irogers@google.com>
Acked/Tested-by: Jiri Olsa <jolsa@kernel.org>
Acked/Tested-by: Jiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andres Freund <andres@anarazel.de>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Christy Lee <christylee@fb.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Quentin Monnet <quentin@isovalent.com>
Cc: Roberto Sassu <roberto.sassu@huawei.com>
Cc: bpf@vger.kernel.org
Link: https://lore.kernel.org/r/20230116010115.490713-2-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf thread_map: Reduce exposure of libperf internal API

Remove unnecessary include of internal threadmap.h and refcount.h in
thread_map.h. Switch to using public APIs when possible or including
the internal header file in the C file. Fix a transitive dependency in
openat-syscall.c broken by the clean up.

Signed-off-by: Ian Rogers <irogers@google.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Nicolas Schier <nicolas@fjasle.eu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: bpf@vger.kernel.org
Link: http://lore.kernel.org/lkml/20221109184914.1357295-13-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf build: Stop using __weak bpf_map_create() to handle older libbpf versions

By adding a feature test for bpf_map_create() and providing a fallback if
it isn't present in older versions of libbpf.

This also fixes the build with torvalds/master at this point:

$ git log --oneline -5 torvalds/master
babf0bb978e3c9fc (torvalds/master) Merge tag 'xfs-5.19-for-linus' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux
e375780b631a5fc2 Merge tag 'fsnotify_for_v5.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs
8b728edc5be16179 Merge tag 'fs_for_v5.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs
3f306ea2e18568f6 Merge tag 'dma-mapping-5.19-2022-05-25' of git://git.infradead.org/users/hch/dma-mapping
fbe86daca0ba878b Merge tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi
$

Coping with:

$ git log --oneline -2 d16495a982324f75
d16495a982324f75 libbpf: remove bpf_create_map*() APIs
e2371b1632b1c61c libbpf: start 1.0 development cycle
$

As the __weak function fails to build as it calls the now removed
bpf_create_map() API.

Testing:

$ rpm -q libbpf-devel
libbpf-devel-0.4.0-2.fc35.x86_64
$
$ make -C tools/perf BUILD_BPF_SKEL=1 LIBBPF_DYNAMIC=1 O=/tmp/build/perf install-bin
$ cat /tmp/build/perf/feature/test-libbpf-bpf_map_create.make.output
test-libbpf-bpf_map_create.c: In function ‘main’:
test-libbpf-bpf_map_create.c:6:16: error: implicit declaration of function ‘bpf_map_create’; did you mean ‘bpf_map_freeze’? [-Werror=implicit-function-declaration]
6 | return bpf_map_create(0 /* map_type */, NULL /* map_name */, 0, /* key_size */,
| ^~~~~~~~~~~~~~
| bpf_map_freeze
test-libbpf-bpf_map_create.c:6:87: error: expected expression before ‘,’ token
6 | return bpf_map_create(0 /* map_type */, NULL /* map_name */, 0, /* key_size */,
| ^
cc1: all warnings being treated as errors
$
$ objdump -dS /tmp/build/perf/perf | grep '<bpf_map_create>:' -A20
000000000058b290 <bpf_map_create>:
{
58b290: 55 push %rbp
58b291: 48 89 e5 mov %rsp,%rbp
58b294: 48 83 ec 10 sub $0x10,%rsp
58b298: 64 48 8b 04 25 28 00 mov %fs:0x28,%rax
58b29f: 00 00
58b2a1: 48 89 45 f8 mov %rax,-0x8(%rbp)
58b2a5: 31 c0 xor %eax,%eax
return bpf_create_map(map_type, key_size, value_size, max_entries, 0);
58b2a7: 48 8b 45 f8 mov -0x8(%rbp),%rax
58b2ab: 64 48 2b 04 25 28 00 sub %fs:0x28,%rax
58b2b2: 00 00
58b2b4: 75 10 jne 58b2c6 <bpf_map_create+0x36>
}
58b2b6: c9 leave
58b2b7: 89 d6 mov %edx,%esi
58b2b9: 89 ca mov %ecx,%edx
58b2bb: 44 89 c1 mov %r8d,%ecx
return bpf_create_map(map_type, key_size, value_size, max_entries, 0);
58b2be: 45 31 c0 xor %r8d,%r8d
$

Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ilya Leoshkevich <iii@linux.ibm.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: Sumanth Korikkar <sumanthk@linux.ibm.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Richter <tmricht@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Link: http://lore.kernel.org/linux-perf-users/Yo+XvQNKL4K5khl2@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf bpf_counter: Tidy use of CPU map index

BPF counters are typically running across all CPUs and so the CPU map
index and CPU number are the same. There may be cases with offline CPUs
where this isn't the case and so ensure the cpu map index for
perf_counts is going to be a valid index by explicitly iterating over
the CPU map. This also makes it clearer that users of perf_counts are
using an index. Collapse some multiple uses of perf_counts into single
uses.

Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Dave Marchevsky <davemarchevsky@fb.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@arm.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: KP Singh <kpsingh@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Lv Ruyi <lv.ruyi@zte.com.cn>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Martin KaFai Lau <kafai@fb.com>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Quentin Monnet <quentin@isovalent.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Xing Zhengjun <zhengjun.xing@linux.intel.com>
Cc: Yonghong Song <yhs@fb.com>
Cc: bpf@vger.kernel.org
Cc: netdev@vger.kernel.org
Link: https://lore.kernel.org/r/20220519032005.1273691-5-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf cpumap: Give CPUs their own type

A common problem is confusing CPU map indices with the CPU, by wrapping
the CPU with a struct then this is avoided. This approach is similar to
atomic_t.

Committer notes:

To make it build with BUILD_BPF_SKEL=1 these files needed the
conversions to 'struct perf_cpu' usage:

tools/perf/util/bpf_counter.c
tools/perf/util/bpf_counter_cgroup.c
tools/perf/util/bpf_ftrace.c

Also perf_env__get_cpu() was removed back in "perf cpumap: Switch
cpu_map__build_map to cpu function".

Additionally these needed to be fixed for the ARM builds to complete:

tools/perf/arch/arm/util/cs-etm.c
tools/perf/arch/arm64/util/pmu.c

Suggested-by: John Garry <john.garry@huawei.com>
Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@arm.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kajol Jain <kjain@linux.ibm.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Clarke <pc@us.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Riccardo Mancini <rickyman7@gmail.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Suzuki Poulouse <suzuki.poulose@arm.com>
Cc: Vineet Singh <vineet.singh@intel.com>
Cc: coresight@lists.linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: zhengjun.xing@intel.com
Link: https://lore.kernel.org/r/20220105061351.120843-49-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf bpf: Rename 'cpu' to 'cpu_map_idx'

Synchronize the caller in evsel with the called function.

Shorten 3 lines of code in bperf_read by using
perf_cpu_map__for_each_cpu().

This code is frequently using variables named cpu as cpu map indices,
which doesn't matter as all CPUs are in the CPU map. It is strange in
some cases the cpumap is used at all.

Committer notes:

Found when building with BUILD_BPF_SKEL=1:

Remove unused 'num_cpu' variable in bperf__read().

Make 'j' an 'int' as it is used in perf_cpu_map__for_each_cpu() to compare against an 'int'

Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@arm.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: John Garry <john.garry@huawei.com>
Cc: Kajol Jain <kjain@linux.ibm.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Clarke <pc@us.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Riccardo Mancini <rickyman7@gmail.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Suzuki Poulouse <suzuki.poulose@arm.com>
Cc: Vineet Singh <vineet.singh@intel.com>
Cc: coresight@lists.linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: zhengjun.xing@intel.com
Link: https://lore.kernel.org/r/20220105061351.120843-45-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf/bpf_counter: Use bpf_map_create instead of bpf_create_map

bpf_create_map is deprecated. Replace it with bpf_map_create. Also add a
__weak bpf_map_create() so that when older version of libbpf is linked as
a shared library, it falls back to bpf_create_map().

Fixes: 992c4225419a ("libbpf: Unify low-level map creation APIs w/ new bpf_map_create()")
Signed-off-by: Song Liu <song@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20211207232340.2561471-1-song@kernel.org

perf: Pull in bpf_program__get_prog_info_linear

To prepare for impending deprecation of libbpf's
bpf_program__get_prog_info_linear, pull in the function and associated
helpers into the perf codebase and migrate existing uses to the perf
copy.

Since libbpf's deprecated definitions will still be visible to perf, it
is necessary to rename perf's definitions.

Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Song Liu <songliubraving@fb.com>
Acked-by: Quentin Monnet <quentin@isovalent.com>
Link: https://lore.kernel.org/bpf/20211101224357.2651181-4-davemarchevsky@fb.com

perf bpf: Pull in bpf_program__get_prog_info_linear()

To prepare for impending deprecation of libbpf's bpf_program__get_prog_info_linear(),
pull in the function and associated helpers into the perf codebase and migrate
existing uses to the perf copy.

Since libbpf's deprecated definitions will still be visible to perf, it is necessary
to rename perf's definitions.

Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Song Liu <songliubraving@fb.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20211011082031.4148337-4-davemarchevsky@fb.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf bpf: Deprecate bpf_map__resize() in favor of bpf_map_set_max_entries()

As a part of libbpf 1.0 plan[0], this patch deprecates use of
bpf_map__resize in favour of bpf_map__set_max_entries.

Reference: https://github.com/libbpf/libbpf/issues/304
[0]: https://github.com/libbpf/libbpf/wiki/Libbpf:-the-road-to-v1.0#libbpfh-high-level-apis

Signed-off-by: Muhammad Falak R Wani <falakreyaz@gmail.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: KP Singh <kpsingh@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Martin KaFai Lau <kafai@fb.com>
Cc: Muhammad Falak R Wani <falakreyaz@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Quentin Monnet <quentin@isovalent.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: Yu Kuai <yukuai3@huawei.com>
Link: http //lore.kernel.org/lkml/20210815103610.27887-1-falakreyaz@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools: Replace btf__get_from_id() with btf__load_from_kernel_by_id()

Replace the calls to function btf__get_from_id(), which we plan to
deprecate before the library reaches v1.0, with calls to
btf__load_from_kernel_by_id() in tools/ (bpftool, perf, selftests).
Update the surrounding code accordingly (instead of passing a pointer to
the btf struct, get it as a return value from the function).

Signed-off-by: Quentin Monnet <quentin@isovalent.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20210729162028.29512-6-quentin@isovalent.com

tools: Free BTF objects at various locations

Make sure to call btf__free() (and not simply free(), which does not
free all pointers stored in the struct) on pointers to struct btf
objects retrieved at various locations.

These were found while updating the calls to btf__get_from_id().

Fixes: 999d82cbc044 ("tools/bpf: enhance test_btf file testing to test func info")
Fixes: 254471e57a86 ("tools/bpf: bpftool: add support for func types")
Fixes: 7b612e291a5a ("perf tools: Synthesize PERF_RECORD_* for loaded BPF programs")
Fixes: d56354dc4909 ("perf tools: Save bpf_prog_info and BTF of new BPF programs")
Fixes: 47c09d6a9f67 ("bpftool: Introduce "prog profile" command")
Fixes: fa853c4b839e ("perf stat: Enable counting events for BPF programs")
Signed-off-by: Quentin Monnet <quentin@isovalent.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210729162028.29512-5-quentin@isovalent.com

libperf: Move 'leader' from tools/perf to perf_evsel::leader

Move evsel::leader to perf_evsel::leader, so we can move the group
interface to libperf.

Also add several evsel helpers to ease up the transition:

struct evsel *evsel__leader(struct evsel *evsel);
- get leader evsel

bool evsel__has_leader(struct evsel *evsel, struct evsel *leader);
- true if evsel has leader as leader

bool evsel__is_leader(struct evsel *evsel);
- true if evsel is itw own leader

void evsel__set_leader(struct evsel *evsel, struct evsel *leader);
- set leader for evsel

Committer notes:

Fix this when building with 'make BUILD_BPF_SKEL=1'

tools/perf/util/bpf_counter.c

- if (evsel->leader->core.nr_members > 1) {
+ if (evsel->core.leader->nr_members > 1) {

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Requested-by: Shunsuke Nakamura <nakamura.shun@fujitsu.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/20210706151704.73662-4-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf stat: Enable BPF counter with --for-each-cgroup

Recently bperf was added to use BPF to count perf events for various
purposes. This is an extension for the approach and targetting to
cgroup usages.

Unlike the other bperf, it doesn't share the events with other
processes but it'd reduce unnecessary events (and the overhead of
multiplexing) for each monitored cgroup within the perf session.

When --for-each-cgroup is used with --bpf-counters, it will open
cgroup-switches event per cpu internally and attach the new BPF
program to read given perf_events and to aggregate the results for
cgroups. It's only called when task is switched to a task in a
different cgroup.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Song Liu <songliubraving@fb.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lore.kernel.org/lkml/20210701211227.1403788-1-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf bpf_counter: Move common functions to bpf_counter.h

Some helper functions will be used for cgroup counting too. Move them
to a header file for sharing.

Committer notes:

Fix the build on older systems with:

- struct bpf_map_info map_info = {0};
+ struct bpf_map_info map_info = { .id = 0, };

This wasn't breaking the build in such systems as bpf_counter.c isn't
built due to:

tools/perf/util/Build:

perf-$(CONFIG_PERF_BPF_SKEL) += bpf_counter.o

The bpf_counter.h file on the other hand is included from places that
are built everywhere.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Song Liu <songliubraving@fb.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lore.kernel.org/lkml/20210625071826.608504-4-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf stat: Fix error return code in bperf__load()

Fix to return a negative error code from the error handling case instead
of 0, as done elsewhere in this function.

Committer notes:

Added the missing {} for the now multiline 'if' block, fixing this error:

CC /tmp/build/perf/util/bpf_counter.o
util/bpf_counter.c: In function ‘bperf__load’:
util/bpf_counter.c:523:9: error: this ‘if’ clause does not guard... [-Werror=misleading-indentation]
523 | if (evsel->bperf_leader_link_fd < 0 &&
| ^~
util/bpf_counter.c:526:17: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the ‘if’
526 | goto out;
| ^~~~
cc1: all warnings being treated as errors

Fixes: 7fac83aaf2eecc9e ("perf stat: Introduce 'bperf' to share hardware PMCs with BPF")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: Yu Kuai <yukuai3@huawei.com>
Cc: Zhang Yi <yi.zhang@huawei.com>
Link: http://lore.kernel.org/lkml/20210517081254.1561564-1-yukuai3@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf stat: Fix error check for bpf_program__attach

It seems the bpf_program__attach() returns a negative error code instead
of a NULL pointer in case of error.

Fixes: 7fac83aaf2ee ("perf stat: Introduce 'bperf' to share hardware PMCs with BPF")
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <songliubraving@fb.com>
Link: http://lore.kernel.org/lkml/20210527220052.1657578-1-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf stat: Introduce bpf_counter_ops->disable()

Introduce bpf_counter_ops->disable(), which is used stop counting the
event.

Committer notes:

Added a dummy bpf_counter__disable() to the python binding to avoid
having 'perf test python' failing.

bpf_counter isn't supported in the python binding.

Signed-off-by: Song Liu <song@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: kernel-team@fb.com
Link: https://lore.kernel.org/r/20210425214333.1090950-6-song@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf stat: Introduce ':b' modifier

Introduce 'b' modifier to event parser, which means use BPF program to
manage this event. This is the same as --bpf-counters option, but only
applies to this event. For example,

perf stat -e cycles:b,cs # use bpf for cycles, but not cs
perf stat -e cycles,cs --bpf-counters # use bpf for both cycles and cs

Suggested-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Song Liu <song@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/r/20210425214333.1090950-5-song@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf stat: Introduce config stat.bpf-counter-events

Currently, to use BPF to aggregate perf event counters, the user uses
--bpf-counters option. Enable "use bpf by default" events with a config
option, stat.bpf-counter-events. Events with name in the option will use
BPF.

This also enables mixed BPF event and regular event in the same sesssion.
For example:

perf config stat.bpf-counter-events=instructions
perf stat -e instructions,cs

The second command will use BPF for "instructions" but not "cs".

Signed-off-by: Song Liu <song@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/r/20210425214333.1090950-4-song@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf bpf: check perf_attr_map is compatible with the perf binary

perf_attr_map could be shared among different version of perf binary. Add
bperf_attr_map_compatible() to check whether the existing attr_map is
compatible with current perf binary.

Signed-off-by: Song Liu <song@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: kernel-team@fb.com
Link: https://lore.kernel.org/r/20210425214333.1090950-3-song@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf util: Move bpf_perf definitions to a libperf header

By following the same protocol, other tools can share hardware PMCs with
perf. Move perf_event_attr_map_entry and BPF_PERF_DEFAULT_ATTR_MAP_PATH to
bpf_perf.h for other tools to use.

Signed-off-by: Song Liu <song@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: kernel-team@fb.com
Link: https://lore.kernel.org/r/20210425214333.1090950-2-song@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf stat: Introduce 'bperf' to share hardware PMCs with BPF

The perf tool uses performance monitoring counters (PMCs) to monitor
system performance. The PMCs are limited hardware resources. For
example, Intel CPUs have 3x fixed PMCs and 4x programmable PMCs per cpu.

Modern data center systems use these PMCs in many different ways: system
level monitoring, (maybe nested) container level monitoring, per process
monitoring, profiling (in sample mode), etc. In some cases, there are
more active perf_events than available hardware PMCs. To allow all
perf_events to have a chance to run, it is necessary to do expensive
time multiplexing of events.

On the other hand, many monitoring tools count the common metrics
(cycles, instructions). It is a waste to have multiple tools create
multiple perf_events of "cycles" and occupy multiple PMCs.

bperf tries to reduce such wastes by allowing multiple perf_events of
"cycles" or "instructions" (at different scopes) to share PMUs. Instead
of having each perf-stat session to read its own perf_events, bperf uses
BPF programs to read the perf_events and aggregate readings to BPF maps.
Then, the perf-stat session(s) reads the values from these BPF maps.

Please refer to the comment before the definition of bperf_ops for the
description of bperf architecture.

bperf is off by default. To enable it, pass --bpf-counters option to
perf-stat. bperf uses a BPF hashmap to share information about BPF
programs and maps used by bperf. This map is pinned to bpffs. The
default path is /sys/fs/bpf/perf_attr_map. The user could change the
path with option --bpf-attr-map.

Committer testing:

# dmesg|grep "Performance Events" -A5
[ 0.225277] Performance Events: Fam17h+ core perfctr, AMD PMU driver.
[ 0.225280] ... version: 0
[ 0.225280] ... bit width: 48
[ 0.225281] ... generic registers: 6
[ 0.225281] ... value mask: 0000ffffffffffff
[ 0.225281] ... max period: 00007fffffffffff
#
# for a in $(seq 6) ; do perf stat -a -e cycles,instructions sleep 100000 & done
[1] 2436231
[2] 2436232
[3] 2436233
[4] 2436234
[5] 2436235
[6] 2436236
# perf stat -a -e cycles,instructions sleep 0.1

Performance counter stats for 'system wide':

310,326,987 cycles (41.87%)
236,143,290 instructions # 0.76 insn per cycle (41.87%)

0.100800885 seconds time elapsed

#

We can see that the counters were enabled for this workload 41.87% of
the time.

Now with --bpf-counters:

# for a in $(seq 32) ; do perf stat --bpf-counters -a -e cycles,instructions sleep 100000 & done
[1] 2436514
[2] 2436515
[3] 2436516
[4] 2436517
[5] 2436518
[6] 2436519
[7] 2436520
[8] 2436521
[9] 2436522
[10] 2436523
[11] 2436524
[12] 2436525
[13] 2436526
[14] 2436527
[15] 2436528
[16] 2436529
[17] 2436530
[18] 2436531
[19] 2436532
[20] 2436533
[21] 2436534
[22] 2436535
[23] 2436536
[24] 2436537
[25] 2436538
[26] 2436539
[27] 2436540
[28] 2436541
[29] 2436542
[30] 2436543
[31] 2436544
[32] 2436545
#
# ls -la /sys/fs/bpf/perf_attr_map
-rw-------. 1 root root 0 Mar 23 14:53 /sys/fs/bpf/perf_attr_map
# bpftool map | grep bperf | wc -l
64
#

# bpftool map | tail
1265: percpu_array name accum_readings flags 0x0
key 4B value 24B max_entries 1 memlock 4096B
1266: hash name filter flags 0x0
key 4B value 4B max_entries 1 memlock 4096B
1267: array name bperf_fo.bss flags 0x400
key 4B value 8B max_entries 1 memlock 4096B
btf_id 996
pids perf(2436545)
1268: percpu_array name accum_readings flags 0x0
key 4B value 24B max_entries 1 memlock 4096B
1269: hash name filter flags 0x0
key 4B value 4B max_entries 1 memlock 4096B
1270: array name bperf_fo.bss flags 0x400
key 4B value 8B max_entries 1 memlock 4096B
btf_id 997
pids perf(2436541)
1285: array name pid_iter.rodata flags 0x480
key 4B value 4B max_entries 1 memlock 4096B
btf_id 1017 frozen
pids bpftool(2437504)
1286: array flags 0x0
key 4B value 32B max_entries 1 memlock 4096B
#
# bpftool map dump id 1268 | tail
value (CPU 21):
8f f3 bc ca 00 00 00 00 80 fd 2a d1 4d 00 00 00
80 fd 2a d1 4d 00 00 00
value (CPU 22):
7e d5 64 4d 00 00 00 00 a4 8a 2e ee 4d 00 00 00
a4 8a 2e ee 4d 00 00 00
value (CPU 23):
a7 78 3e 06 01 00 00 00 b2 34 94 f6 4d 00 00 00
b2 34 94 f6 4d 00 00 00
Found 1 element
# bpftool map dump id 1268 | tail
value (CPU 21):
c6 8b d9 ca 00 00 00 00 20 c6 fc 83 4e 00 00 00
20 c6 fc 83 4e 00 00 00
value (CPU 22):
9c b4 d2 4d 00 00 00 00 3e 0c df 89 4e 00 00 00
3e 0c df 89 4e 00 00 00
value (CPU 23):
18 43 66 06 01 00 00 00 5b 69 ed 83 4e 00 00 00
5b 69 ed 83 4e 00 00 00
Found 1 element
# bpftool map dump id 1268 | tail
value (CPU 21):
f2 6e db ca 00 00 00 00 92 67 4c ba 4e 00 00 00
92 67 4c ba 4e 00 00 00
value (CPU 22):
dc 8e e1 4d 00 00 00 00 d9 32 7a c5 4e 00 00 00
d9 32 7a c5 4e 00 00 00
value (CPU 23):
bd 2b 73 06 01 00 00 00 7c 73 87 bf 4e 00 00 00
7c 73 87 bf 4e 00 00 00
Found 1 element
#

# perf stat --bpf-counters -a -e cycles,instructions sleep 0.1

Performance counter stats for 'system wide':

119,410,122 cycles
152,105,479 instructions # 1.27 insn per cycle

0.101395093 seconds time elapsed

#

See? We had the counters enabled all the time.

Signed-off-by: Song Liu <songliubraving@fb.com>
Reviewed-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: kernel-team@fb.com
Link: http://lore.kernel.org/lkml/20210316211837.910506-2-songliubraving@fb.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf stat: Enable counting events for BPF programs

Introduce 'perf stat -b' option, which counts events for BPF programs, like:

[root@localhost ~]# ~/perf stat -e ref-cycles,cycles -b 254 -I 1000
1.487903822 115,200 ref-cycles
1.487903822 86,012 cycles
2.489147029 80,560 ref-cycles
2.489147029 73,784 cycles
3.490341825 60,720 ref-cycles
3.490341825 37,797 cycles
4.491540887 37,120 ref-cycles
4.491540887 31,963 cycles

The example above counts 'cycles' and 'ref-cycles' of BPF program of id
254. This is similar to bpftool-prog-profile command, but more
flexible.

'perf stat -b' creates per-cpu perf_event and loads fentry/fexit BPF
programs (monitor-progs) to the target BPF program (target-prog). The
monitor-progs read perf_event before and after the target-prog, and
aggregate the difference in a BPF map. Then the user space reads data
from these maps.

A new 'struct bpf_counter' is introduced to provide a common interface
that uses BPF programs/maps to count perf events.

Committer notes:

Removed all but bpf_counter.h includes from evsel.h, not needed at all.

Also BPF map lookups for PERCPU_ARRAYs need to have as its value receive
buffer passed to the kernel libbpf_num_possible_cpus() entries, not
evsel__nr_cpus(evsel), as the former uses
/sys/devices/system/cpu/possible while the later uses
/sys/devices/system/cpu/online, which may be less than the 'possible'
number making the bpf map lookup overwrite memory and cause hard to
debug memory corruption.

We need to continue using evsel__nr_cpus(evsel) when accessing the
perf_counts array tho, not to overwrite another are of memory :-)

Signed-off-by: Song Liu <songliubraving@fb.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Link: https://lore.kernel.org/lkml/20210120163031.GU12699@kernel.org/
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: kernel-team@fb.com
Link: http://lore.kernel.org/lkml/20201229214214.3413833-4-songliubraving@fb.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>