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17 Commits
| Author | SHA1 | Message | Date | |
|---|---|---|---|---|
Howard Chu
|
9557c00076 |
perf record --off-cpu: Add --off-cpu-thresh option
Specify the threshold for dumping offcpu samples with --off-cpu-thresh,
the unit is milliseconds. Default value is 500ms.
Example:
perf record --off-cpu --off-cpu-thresh 824
The example above collects direct off-cpu samples where the off-cpu time
is longer than 824ms.
Committer testing:
After commenting out the end off-cpu dump to have just the ones that are
added right after the task is scheduled back, and using a threshould of
1000ms, we see some periods (the 5th column, just before "offcpu-time"
in the 'perf script' output) that are over 1000.000.000 nanoseconds:
root@number:~# perf record --off-cpu --off-cpu-thresh 10000
^C[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 3.902 MB perf.data (34335 samples) ]
root@number:~# perf script
<SNIP>
Isolated Web Co 59932 [028] 63839.594437: 1000049427 offcpu-time:
7fe63c7976c2 __syscall_cancel_arch_end+0x0 (/usr/lib64/libc.so.6)
7fe63c78c04c __futex_abstimed_wait_common+0x7c (/usr/lib64/libc.so.6)
7fe63c78e928 pthread_cond_timedwait@@GLIBC_2.3.2+0x178 (/usr/lib64/libc.so.6)
5599974a9fe7 mozilla::detail::ConditionVariableImpl::wait_for(mozilla::detail::MutexImpl&, mozilla::BaseTimeDuration<mozilla::TimeDurationValueCalculator> const&)+0xe7 (/usr/lib64/fir>
100000000 [unknown] ([unknown])
swapper 0 [025] 63839.594459: 195724 cycles:P: ffffffffac328270 read_tsc+0x0 ([kernel.kallsyms])
Isolated Web Co 59932 [010] 63839.594466: 1000055278 offcpu-time:
7fe63c7976c2 __syscall_cancel_arch_end+0x0 (/usr/lib64/libc.so.6)
7fe63c78ba24 __syscall_cancel+0x14 (/usr/lib64/libc.so.6)
7fe63c804c4e __poll+0x1e (/usr/lib64/libc.so.6)
7fe633b0d1b8 PollWrapper(_GPollFD*, unsigned int, int) [clone .lto_priv.0]+0xf8 (/usr/lib64/firefox/libxul.so)
10000002c [unknown] ([unknown])
swapper 0 [027] 63839.594475: 134433 cycles:P: ffffffffad4c45d9 irqentry_enter+0x19 ([kernel.kallsyms])
swapper 0 [028] 63839.594499: 215838 cycles:P: ffffffffac39199a switch_mm_irqs_off+0x10a ([kernel.kallsyms])
MediaPD~oder #1 1407676 [027] 63839.594514: 134433 cycles:P: 7f982ef5e69f dct_IV(int*, int, int*)+0x24f (/usr/lib64/libfdk-aac.so.2.0.0)
swapper 0 [024] 63839.594524: 267411 cycles:P: ffffffffad4c6ee6 poll_idle+0x56 ([kernel.kallsyms])
MediaSu~sor #75 1093827 [026] 63839.594555: 332652 cycles:P: 55be753ad030 moz_xmalloc+0x200 (/usr/lib64/firefox/firefox)
swapper 0 [027] 63839.594616: 160548 cycles:P: ffffffffad144840 menu_select+0x570 ([kernel.kallsyms])
Isolated Web Co 14019 [027] 63839.595120: 1000050178 offcpu-time:
7fc9537cc6c2 __syscall_cancel_arch_end+0x0 (/usr/lib64/libc.so.6)
7fc9537c104c __futex_abstimed_wait_common+0x7c (/usr/lib64/libc.so.6)
7fc9537c3928 pthread_cond_timedwait@@GLIBC_2.3.2+0x178 (/usr/lib64/libc.so.6)
7fc95372a3c8 pt_TimedWait+0xb8 (/usr/lib64/libnspr4.so)
7fc95372a8d8 PR_WaitCondVar+0x68 (/usr/lib64/libnspr4.so)
7fc94afb1f7c WatchdogMain(void*)+0xac (/usr/lib64/firefox/libxul.so)
7fc947498660 [unknown] ([unknown])
7fc9535fce88 [unknown] ([unknown])
7fc94b620e60 WatchdogManager::~WatchdogManager()+0x0 (/usr/lib64/firefox/libxul.so)
fff8548387f8b48 [unknown] ([unknown])
swapper 0 [003] 63839.595712: 212948 cycles:P: ffffffffacd5b865 acpi_os_read_port+0x55 ([kernel.kallsyms])
<SNIP>
Suggested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Suggested-by: Ian Rogers <irogers@google.com>
Suggested-by: Namhyung Kim <namhyung@kernel.org>
Reviewed-by: Ian Rogers <irogers@google.com>
Signed-off-by: Howard Chu <howardchu95@gmail.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Tested-by: Gautam Menghani <gautam@linux.ibm.com>
Tested-by: Ian Rogers <irogers@google.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@linaro.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20241108204137.2444151-2-howardchu95@gmail.com
Link: https://lore.kernel.org/r/20250501022809.449767-10-howardchu95@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
|
||
|
Howard Chu
|
74069a0160 |
perf record --off-cpu: Dump the remaining PERF_SAMPLE_ in sample_type from BPF's stack trace map
Dump the remaining PERF_SAMPLE_ data, as if it is dumping a direct sample. Put the stack trace, tid, off-cpu time and cgroup id into the raw_data section, just like a direct off-cpu sample coming from BPF's bpf_perf_event_output(). This ensures that evsel__parse_sample() correctly parses both direct samples and accumulated samples. Suggested-by: Namhyung Kim <namhyung@kernel.org> Reviewed-by: Ian Rogers <irogers@google.com> Signed-off-by: Howard Chu <howardchu95@gmail.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Tested-by: Gautam Menghani <gautam@linux.ibm.com> Tested-by: Ian Rogers <irogers@google.com> Acked-by: Namhyung Kim <namhyung@kernel.org> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: James Clark <james.clark@linaro.org> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Kan Liang <kan.liang@linux.intel.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: https://lore.kernel.org/r/20241108204137.2444151-10-howardchu95@gmail.com Link: https://lore.kernel.org/r/20250501022809.449767-9-howardchu95@gmail.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> |
||
|
Howard Chu
|
282c195906 |
perf record --off-cpu: Preparation of off-cpu BPF program
Set the perf_event map in BPF for dumping off-cpu samples, and set the offcpu_thresh to specify the threshold. Reviewed-by: Ian Rogers <irogers@google.com> Signed-off-by: Howard Chu <howardchu95@gmail.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Tested-by: Gautam Menghani <gautam@linux.ibm.com> Tested-by: Ian Rogers <irogers@google.com> Acked-by: Namhyung Kim <namhyung@kernel.org> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: James Clark <james.clark@linaro.org> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Kan Liang <kan.liang@linux.intel.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: https://lore.kernel.org/r/20241108204137.2444151-5-howardchu95@gmail.com Link: https://lore.kernel.org/r/20250501022809.449767-4-howardchu95@gmail.com [ Added some missing iteration variables to off_cpu_config() and fixed up a manually edited patch hunk line boundary line ] Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> |
||
|
Howard Chu
|
0f72027bb9 |
perf record --off-cpu: Parse off-cpu event
Parse the off-cpu event using parse_event(), as bpf-output.
Call evlist__enable_evsel() on off-cpu event. This fixes the inability
to collect direct off-cpu samples on a workload, as reported by Arnaldo
Carvalho de Melo <acme@redhat.com>.
The reason being, workload sets enable_on_exec instead of calling
evlist__enable(), but off-cpu event does not attach to an executable and
execve won't be called, so the fds from perf_event_open() are not
enabled.
no-inherit should be set to 1, here's the reason:
We update the BPF perf_event map for direct off-cpu sample dumping (in
following patches), it executes as follows:
bpf_map_update_value()
bpf_fd_array_map_update_elem()
perf_event_fd_array_get_ptr()
perf_event_read_local()
In perf_event_read_local(), there is:
int perf_event_read_local(struct perf_event *event, u64 *value,
u64 *enabled, u64 *running)
{
...
/*
* It must not be an event with inherit set, we cannot read
* all child counters from atomic context.
*/
if (event->attr.inherit) {
ret = -EOPNOTSUPP;
goto out;
}
Which means no-inherit has to be true for updating the BPF perf_event
map.
Moreover, for bpf-output events, we primarily want a system-wide event
instead of a per-task event.
The reason is that in BPF's bpf_perf_event_output(), BPF uses the CPU
index to retrieve the perf_event file descriptor it outputs to.
Making a bpf-output event system-wide naturally satisfies this
requirement by mapping CPU appropriately.
Suggested-by: Namhyung Kim <namhyung@kernel.org>
Reviewed-by: Ian Rogers <irogers@google.com>
Signed-off-by: Howard Chu <howardchu95@gmail.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Tested-by: Gautam Menghani <gautam@linux.ibm.com>
Tested-by: Ian Rogers <irogers@google.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@linaro.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20241108204137.2444151-4-howardchu95@gmail.com
Link: https://lore.kernel.org/r/20250501022809.449767-3-howardchu95@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
|
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Athira Rajeev
|
2adbf5349a |
perf record: Fix segfault with --off-cpu when debuginfo is not enabled
When kernel is built without debuginfo, running 'perf record' with --off-cpu results in segfault as below: ./perf record --off-cpu -e dummy sleep 1 libbpf: kernel BTF is missing at '/sys/kernel/btf/vmlinux', was CONFIG_DEBUG_INFO_BTF enabled? libbpf: failed to find '.BTF' ELF section in /lib/modules/6.13.0-rc3+/build/vmlinux libbpf: failed to find valid kernel BTF Segmentation fault (core dumped) The backtrace pointed to: #0 0x00000000100fb17c in btf.type_cnt () #1 0x00000000100fc1a8 in btf_find_by_name_kind () #2 0x00000000100fc38c in btf.find_by_name_kind () #3 0x00000000102ee3ac in off_cpu_prepare () #4 0x000000001002f78c in cmd_record () #5 0x00000000100aee78 in run_builtin () #6 0x00000000100af3e4 in handle_internal_command () #7 0x000000001001004c in main () Code sequence is: static void check_sched_switch_args(void) { struct btf *btf = btf__load_vmlinux_btf(); const struct btf_type *t1, *t2, *t3; u32 type_id; type_id = btf__find_by_name_kind(btf, "btf_trace_sched_switch", BTF_KIND_TYPEDEF); btf__load_vmlinux_btf() fails when CONFIG_DEBUG_INFO_BTF is not enabled. Here bpf__find_by_name_kind() calls btf__type_cnt() with NULL btf value and results in segfault. To fix this, add a check to see if btf is not NULL before invoking bpf__find_by_name_kind(). Reviewed-by: Namhyung Kim <namhyung@kernel.org> Signed-off-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Disha Goel <disgoel@linux.vnet.ibm.com> Cc: Hari Bathini <hbathini@linux.ibm.com> Cc: Ian Rogers <irogers@google.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Kajol Jain <kjain@linux.ibm.com> Cc: Madhavan Srinivasan <maddy@linux.ibm.com> Link: https://lore.kernel.org/r/20241223135813.8175-1-atrajeev@linux.vnet.ibm.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> |
||
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Namhyung Kim
|
8b3b1bb3ea |
perf record offcpu: Constify control data for BPF
The control knobs set before loading BPF programs should be declared as
'const volatile' so that it can be optimized by the BPF core.
Committer testing:
root@x1:~# perf record --off-cpu
^C[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 1.807 MB perf.data (5645 samples) ]
root@x1:~# perf evlist
cpu_atom/cycles/P
cpu_core/cycles/P
offcpu-time
dummy:u
root@x1:~# perf evlist -v
cpu_atom/cycles/P: type: 0 (PERF_TYPE_HARDWARE), size: 136, config: 0xa00000000, { sample_period, sample_freq }: 4000, sample_type: IP|TID|TIME|CPU|PERIOD|IDENTIFIER, read_format: ID|LOST, disabled: 1, inherit: 1, freq: 1, precise_ip: 3, sample_id_all: 1
cpu_core/cycles/P: type: 0 (PERF_TYPE_HARDWARE), size: 136, config: 0x400000000, { sample_period, sample_freq }: 4000, sample_type: IP|TID|TIME|CPU|PERIOD|IDENTIFIER, read_format: ID|LOST, disabled: 1, inherit: 1, freq: 1, precise_ip: 3, sample_id_all: 1
offcpu-time: type: 1 (software), size: 136, config: 0xa (PERF_COUNT_SW_BPF_OUTPUT), { sample_period, sample_freq }: 1, sample_type: IP|TID|TIME|CALLCHAIN|CPU|PERIOD|IDENTIFIER, read_format: ID|LOST, disabled: 1, inherit: 1, freq: 1, sample_id_all: 1
dummy:u: type: 1 (software), size: 136, config: 0x9 (PERF_COUNT_SW_DUMMY), { sample_period, sample_freq }: 1, sample_type: IP|TID|TIME|CPU|IDENTIFIER, read_format: ID|LOST, inherit: 1, exclude_kernel: 1, exclude_hv: 1, mmap: 1, comm: 1, task: 1, sample_id_all: 1, exclude_guest: 1, mmap2: 1, comm_exec: 1, ksymbol: 1, bpf_event: 1
root@x1:~# perf trace -e bpf --max-events 5 perf record --off-cpu
0.000 ( 0.015 ms): :2949124/2949124 bpf(cmd: 36, uattr: 0x7ffefc6dbe30, size: 8) = -1 EOPNOTSUPP (Operation not supported)
0.031 ( 0.115 ms): :2949124/2949124 bpf(cmd: PROG_LOAD, uattr: 0x7ffefc6dbb60, size: 148) = 14
0.159 ( 0.037 ms): :2949124/2949124 bpf(cmd: PROG_LOAD, uattr: 0x7ffefc6dbc20, size: 148) = 14
23.868 ( 0.144 ms): perf/2949124 bpf(cmd: PROG_LOAD, uattr: 0x7ffefc6dbad0, size: 148) = 14
24.027 ( 0.014 ms): perf/2949124 bpf(uattr: 0x7ffefc6dbc80, size: 80) = 14
root@x1:~#
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20240902200515.2103769-6-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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Ian Rogers
|
67a3ebf1c3 |
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> |
||
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Namhyung Kim
|
0e501a65d3 |
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:
|
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Namhyung Kim
|
167b266bf6 |
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:
|
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Namhyung Kim
|
d23477637a |
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>
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Namhyung Kim
|
d6f415ca33 |
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> |
||
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Namhyung Kim
|
07fc958b0c |
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>
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Namhyung Kim
|
49c692b7df |
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:
|
||
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Namhyung Kim
|
685439a7a0 |
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>
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Namhyung Kim
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b36888f71c |
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> |
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Namhyung Kim
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10742d0c07 |
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:
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Namhyung Kim
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edc41a1099 |
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>
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