perf offcpu: Add missed btf_free

Caught by address/leak sanitizer.

Signed-off-by: Ian Rogers <irogers@google.com>
Cc: K Prateek Nayak <kprateek.nayak@amd.com>
Cc: Ravi Bangoria <ravi.bangoria@amd.com>
Cc: Sandipan Das <sandipan.das@amd.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: German Gomez <german.gomez@arm.com>
Cc: James Clark <james.clark@arm.com>
Cc: Nick Terrell <terrelln@fb.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Changbin Du <changbin.du@huawei.com>
Cc: liuwenyu <liuwenyu7@huawei.com>
Cc: Yang Jihong <yangjihong1@huawei.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: Song Liu <song@kernel.org>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Kajol Jain <kjain@linux.ibm.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Cc: Yanteng Si <siyanteng@loongson.cn>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Link: https://lore.kernel.org/r/20231024222353.3024098-8-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>

perf record: Fix BTF type checks in the off-cpu profiling

The BTF func proto for a tracepoint has one more argument than the
actual tracepoint function since it has a context argument at the
begining. So it should compare to 5 when the tracepoint has 4
arguments.

typedef void (*btf_trace_sched_switch)(void *, bool, struct task_struct *, struct task_struct *, unsigned int);

Also, recent change in the perf tool would use a hand-written minimal
vmlinux.h to generate BTF in the skeleton. So it won't have the info
of the tracepoint. Anyway it should use the kernel's vmlinux BTF to
check the type in the kernel.

Fixes: b36888f71c85 ("perf record: Handle argument change in sched_switch")
Reviewed-by: Ian Rogers <irogers@google.com>
Acked-by: Song Liu <song@kernel.org>
Cc: Hao Luo <haoluo@google.com>
CC: bpf@vger.kernel.org
Link: https://lore.kernel.org/r/20230922234444.3115821-1-namhyung@kernel.org
Signed-off-by: Namhyung Kim <namhyung@kernel.org>

perf off_cpu: Fix a typo in BTF tracepoint name, it should be 'btf_trace_sched_switch'

In BTF, tracepoint definitions have the "btf_trace_" prefix. The
off-cpu profiler needs to check the signature of the sched_switch event
using that definition. But there's a typo (s/bpf/btf/) so it failed
always.

Fixes: b36888f71c8542cd ("perf record: Handle argument change in sched_switch")
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: bpf@vger.kernel.org
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20221208182636.524139-1-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf offcpu: Track child processes

When -p option used or a workload is given, it needs to handle child
processes. The perf_event can inherit those task events
automatically. We can add a new BPF program in task_newtask
tracepoint to track child processes.

Before:
$ sudo perf record --off-cpu -- perf bench sched messaging
$ sudo perf report --stat | grep -A1 offcpu
offcpu-time stats:
SAMPLE events: 1

After:
$ sudo perf record -a --off-cpu -- perf bench sched messaging
$ sudo perf report --stat | grep -A1 offcpu
offcpu-time stats:
SAMPLE events: 856

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Blake Jones <blakejones@google.com>
Cc: Hao Luo <haoluo@google.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Milian Wolff <milian.wolff@kdab.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: bpf@vger.kernel.org
Link: https://lore.kernel.org/r/20220811185456.194721-4-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf offcpu: Parse process id separately

The current target code uses thread id for tracking tasks because
perf_events need to be opened for each task. But we can use tgid in
BPF maps and check it easily.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Blake Jones <blakejones@google.com>
Cc: Hao Luo <haoluo@google.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Milian Wolff <milian.wolff@kdab.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: bpf@vger.kernel.org
Link: https://lore.kernel.org/r/20220811185456.194721-3-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf offcpu: Check process id for the given workload

Current task filter checks task->pid which is different for each
thread. But we want to profile all the threads in the process. So
let's compare process id (or thread-group id: tgid) instead.

Before:
$ sudo perf record --off-cpu -- perf bench sched messaging -t
$ sudo perf report --stat | grep -A1 offcpu
offcpu-time stats:
SAMPLE events: 2

After:
$ sudo perf record --off-cpu -- perf bench sched messaging -t
$ sudo perf report --stat | grep -A1 offcpu
offcpu-time stats:
SAMPLE events: 850

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Blake Jones <blakejones@google.com>
Cc: Hao Luo <haoluo@google.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Milian Wolff <milian.wolff@kdab.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: bpf@vger.kernel.org
Link: https://lore.kernel.org/r/20220811185456.194721-2-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf offcpu: Accept allowed sample types only

As offcpu-time event is synthesized at the end, it could not get the
all the sample info. Define OFFCPU_SAMPLE_TYPES for allowed ones and
mask out others in evsel__config() to prevent parse errors.

Because perf sample parsing assumes a specific ordering with the
sample types, setting unsupported one would make it fail to read
data like perf record -d/--data.

Fixes: edc41a1099c2d08c ("perf record: Enable off-cpu analysis with BPF")
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Blake Jones <blakejones@google.com>
Cc: Hao Luo <haoluo@google.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Milian Wolff <milian.wolff@kdab.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: bpf@vger.kernel.org
Link: http://lore.kernel.org/lkml/20220624231313.367909-3-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf record: Add cgroup support for off-cpu profiling

This covers two different use cases. The first one is cgroup
filtering given by -G/--cgroup option which controls the off-cpu
profiling for tasks in the given cgroups only.

The other use case is cgroup sampling which is enabled by
--all-cgroups option and it adds PERF_SAMPLE_CGROUP to the sample_type
to set the cgroup id of the task in the sample data.

Example output.

$ sudo perf record -a --off-cpu --all-cgroups sleep 1

$ sudo perf report --stdio -s comm,cgroup --call-graph=no
...
# Samples: 144 of event 'offcpu-time'
# Event count (approx.): 48452045427
#
# Children Self Command Cgroup
# ........ ........ ............... ..........................................
#
61.57% 5.60% Chrome_ChildIOT /user.slice/user-657345.slice/user@657345.service/app.slice/...
29.51% 7.38% Web Content /user.slice/user-657345.slice/user@657345.service/app.slice/...
17.48% 1.59% Chrome_IOThread /user.slice/user-657345.slice/user@657345.service/app.slice/...
16.48% 4.12% pipewire-pulse /user.slice/user-657345.slice/user@657345.service/session.slice/...
14.48% 2.07% perf /user.slice/user-657345.slice/user@657345.service/app.slice/...
14.30% 7.15% CompositorTileW /user.slice/user-657345.slice/user@657345.service/app.slice/...
13.33% 6.67% Timer /user.slice/user-657345.slice/user@657345.service/app.slice/...
...

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Ian Rogers <irogers@google.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Blake Jones <blakejones@google.com>
Cc: Hao Luo <haoluo@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Milian Wolff <milian.wolff@kdab.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: bpf@vger.kernel.org
Link: https://lore.kernel.org/r/20220518224725.742882-6-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf record: Handle argument change in sched_switch

Recently sched_switch tracepoint added a new argument for prev_state,
but it's hard to handle the change in a BPF program. Instead, we can
check the function prototype in BTF before loading the program.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Ian Rogers <irogers@google.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Blake Jones <blakejones@google.com>
Cc: Hao Luo <haoluo@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Milian Wolff <milian.wolff@kdab.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: bpf@vger.kernel.org
Link: https://lore.kernel.org/r/20220518224725.742882-5-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf record: Implement basic filtering for off-cpu

It should honor cpu and task filtering with -a, -C or -p, -t options.

Committer testing:

# perf record --off-cpu --cpu 1 perf bench sched messaging -l 1000
# Running 'sched/messaging' benchmark:
# 20 sender and receiver processes per group
# 10 groups == 400 processes run

Total time: 1.722 [sec]
[ perf record: Woken up 2 times to write data ]
[ perf record: Captured and wrote 1.446 MB perf.data (7248 samples) ]
#
# perf script | head -20
perf 97164 [001] 38287.696761: 1 cycles: ffffffffb6070174 native_write_msr+0x4 (vmlinux)
perf 97164 [001] 38287.696764: 1 cycles: ffffffffb6070174 native_write_msr+0x4 (vmlinux)
perf 97164 [001] 38287.696765: 9 cycles: ffffffffb6070174 native_write_msr+0x4 (vmlinux)
perf 97164 [001] 38287.696767: 212 cycles: ffffffffb6070176 native_write_msr+0x6 (vmlinux)
perf 97164 [001] 38287.696768: 5130 cycles: ffffffffb6070176 native_write_msr+0x6 (vmlinux)
perf 97164 [001] 38287.696770: 123063 cycles: ffffffffb6e0011e syscall_return_via_sysret+0x38 (vmlinux)
perf 97164 [001] 38287.696803: 2292748 cycles: ffffffffb636c82d __fput+0xad (vmlinux)
swapper 0 [001] 38287.702852: 1927474 cycles: ffffffffb6761378 mwait_idle_with_hints.constprop.0+0x48 (vmlinux)
:97513 97513 [001] 38287.767207: 1172536 cycles: ffffffffb612ff65 newidle_balance+0x5 (vmlinux)
swapper 0 [001] 38287.769567: 1073081 cycles: ffffffffb618216d ktime_get_mono_fast_ns+0xd (vmlinux)
:97533 97533 [001] 38287.770962: 984460 cycles: ffffffffb65b2900 selinux_socket_sendmsg+0x0 (vmlinux)
:97540 97540 [001] 38287.772242: 883462 cycles: ffffffffb6d0bf59 irqentry_exit_to_user_mode+0x9 (vmlinux)
swapper 0 [001] 38287.773633: 741963 cycles: ffffffffb6761378 mwait_idle_with_hints.constprop.0+0x48 (vmlinux)
:97552 97552 [001] 38287.774539: 606680 cycles: ffffffffb62eda0a page_add_file_rmap+0x7a (vmlinux)
:97556 97556 [001] 38287.775333: 502254 cycles: ffffffffb634f964 get_obj_cgroup_from_current+0xc4 (vmlinux)
:97561 97561 [001] 38287.776163: 427891 cycles: ffffffffb61b1522 cgroup_rstat_updated+0x22 (vmlinux)
swapper 0 [001] 38287.776854: 359030 cycles: ffffffffb612fc5e load_balance+0x9ce (vmlinux)
:97567 97567 [001] 38287.777312: 330371 cycles: ffffffffb6a8d8d0 skb_set_owner_w+0x0 (vmlinux)
:97566 97566 [001] 38287.777589: 311622 cycles: ffffffffb614a7a8 native_queued_spin_lock_slowpath+0x148 (vmlinux)
:97512 97512 [001] 38287.777671: 307851 cycles: ffffffffb62e0f35 find_vma+0x55 (vmlinux)
#
# perf record --off-cpu --cpu 4 perf bench sched messaging -l 1000
# Running 'sched/messaging' benchmark:
# 20 sender and receiver processes per group
# 10 groups == 400 processes run

Total time: 1.613 [sec]
[ perf record: Woken up 2 times to write data ]
[ perf record: Captured and wrote 1.415 MB perf.data (6729 samples) ]
# perf script | head -20
perf 97650 [004] 38323.728036: 1 cycles: ffffffffb6070174 native_write_msr+0x4 (vmlinux)
perf 97650 [004] 38323.728040: 1 cycles: ffffffffb6070174 native_write_msr+0x4 (vmlinux)
perf 97650 [004] 38323.728041: 9 cycles: ffffffffb6070174 native_write_msr+0x4 (vmlinux)
perf 97650 [004] 38323.728042: 208 cycles: ffffffffb6070176 native_write_msr+0x6 (vmlinux)
perf 97650 [004] 38323.728044: 5026 cycles: ffffffffb6070176 native_write_msr+0x6 (vmlinux)
perf 97650 [004] 38323.728046: 119970 cycles: ffffffffb6d0bebc syscall_exit_to_user_mode+0x1c (vmlinux)
perf 97650 [004] 38323.728078: 2190103 cycles: 54b756 perf_tool__process_synth_event+0x16 (/home/acme/bin/perf)
swapper 0 [004] 38323.783357: 1593139 cycles: ffffffffb6761378 mwait_idle_with_hints.constprop.0+0x48 (vmlinux)
swapper 0 [004] 38323.785352: 1593139 cycles: ffffffffb6761378 mwait_idle_with_hints.constprop.0+0x48 (vmlinux)
swapper 0 [004] 38323.797330: 1418936 cycles: ffffffffb6761378 mwait_idle_with_hints.constprop.0+0x48 (vmlinux)
swapper 0 [004] 38323.802350: 1418936 cycles: ffffffffb6761378 mwait_idle_with_hints.constprop.0+0x48 (vmlinux)
swapper 0 [004] 38323.806333: 1418936 cycles: ffffffffb6761378 mwait_idle_with_hints.constprop.0+0x48 (vmlinux)
:97996 97996 [004] 38323.807145: 1418936 cycles: 7f5db9be6917 [unknown] ([unknown])
:97959 97959 [004] 38323.807730: 1445074 cycles: ffffffffb6329d36 memcg_slab_post_alloc_hook+0x146 (vmlinux)
:97959 97959 [004] 38323.808103: 1341584 cycles: ffffffffb62fd90f get_page_from_freelist+0x112f (vmlinux)
:97959 97959 [004] 38323.808451: 1227537 cycles: ffffffffb65b2905 selinux_socket_sendmsg+0x5 (vmlinux)
:97959 97959 [004] 38323.808768: 1184321 cycles: ffffffffb6d1ba35 _raw_spin_lock_irqsave+0x15 (vmlinux)
:97959 97959 [004] 38323.809073: 1153017 cycles: ffffffffb6a8d92d skb_set_owner_w+0x5d (vmlinux)
:97959 97959 [004] 38323.809402: 1126875 cycles: ffffffffb6329c64 memcg_slab_post_alloc_hook+0x74 (vmlinux)
:97959 97959 [004] 38323.809695: 1073248 cycles: ffffffffb6e0001d entry_SYSCALL_64+0x1d (vmlinux)
#

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Blake Jones <blakejones@google.com>
Cc: Hao Luo <haoluo@google.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Milian Wolff <milian.wolff@kdab.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: bpf@vger.kernel.org
Link: https://lore.kernel.org/r/20220518224725.742882-4-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf record: Enable off-cpu analysis with BPF

Add --off-cpu option to enable the off-cpu profiling with BPF. It'd
use a bpf_output event and rename it to "offcpu-time". Samples will
be synthesized at the end of the record session using data from a BPF
map which contains the aggregated off-cpu time at context switches.
So it needs root privilege to get the off-cpu profiling.

Each sample will have a separate user stacktrace so it will skip
kernel threads. The sample ip will be set from the stacktrace and
other sample data will be updated accordingly. Currently it only
handles some basic sample types.

The sample timestamp is set to a dummy value just not to bother with
other events during the sorting. So it has a very big initial value
and increase it on processing each samples.

Good thing is that it can be used together with regular profiling like
cpu cycles. If you don't want to that, you can use a dummy event to
enable off-cpu profiling only.

Example output:
$ sudo perf record --off-cpu perf bench sched messaging -l 1000

$ sudo perf report --stdio --call-graph=no
# Total Lost Samples: 0
#
# Samples: 41K of event 'cycles'
# Event count (approx.): 42137343851
...

# Samples: 1K of event 'offcpu-time'
# Event count (approx.): 587990831640
#
# Children Self Command Shared Object Symbol
# ........ ........ ............... .................. .........................
#
81.66% 0.00% sched-messaging libc-2.33.so [.] __libc_start_main
81.66% 0.00% sched-messaging perf [.] cmd_bench
81.66% 0.00% sched-messaging perf [.] main
81.66% 0.00% sched-messaging perf [.] run_builtin
81.43% 0.00% sched-messaging perf [.] bench_sched_messaging
40.86% 40.86% sched-messaging libpthread-2.33.so [.] __read
37.66% 37.66% sched-messaging libpthread-2.33.so [.] __write
2.91% 2.91% sched-messaging libc-2.33.so [.] __poll
...

As you can see it spent most of off-cpu time in read and write in
bench_sched_messaging(). The --call-graph=no was added just to make
the output concise here.

It uses perf hooks facility to control BPF program during the record
session rather than adding new BPF/off-cpu specific calls.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Ian Rogers <irogers@google.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Blake Jones <blakejones@google.com>
Cc: Hao Luo <haoluo@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Milian Wolff <milian.wolff@kdab.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: bpf@vger.kernel.org
Link: https://lore.kernel.org/r/20220518224725.742882-3-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>