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Message-ID: <20240807153843.3231451-1-howardchu95@gmail.com>
Date: Wed, 7 Aug 2024 23:38:34 +0800
From: Howard Chu <howardchu95@...il.com>
To: namhyung@...nel.org
Cc: irogers@...gle.com,
acme@...nel.org,
adrian.hunter@...el.com,
jolsa@...nel.org,
kan.liang@...ux.intel.com,
linux-perf-users@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: [PATCH v4 0/9] perf record --off-cpu: Dump off-cpu samples directly
Changes in v4:
- Minimize the size of data output by perf_event_output()
- Keep only one off-cpu event
- Change off-cpu threshold's unit to microseconds
- Set a default off-cpu threshold
- Print the correct error message for the field 'embed' in perf data header
Changes in v3:
- Add off-cpu-thresh argument
- Process direct off-cpu samples in post
Changes in v2:
- Remove unnecessary comments.
- Rename function off_cpu_change_type to off_cpu_prepare_parse
v1:
As mentioned in: https://bugzilla.kernel.org/show_bug.cgi?id=207323
Currently, off-cpu samples are dumped when perf record is exiting. This
results in off-cpu samples being after the regular samples. This patch
series makes possible dumping off-cpu samples on-the-fly, directly into
perf ring buffer. And it dispatches those samples to the correct format
for perf.data consumers.
Before:
```
migration/0 21 [000] 27981.041319: 2944637851 cycles:P: ffffffff90d2e8aa record_times+0xa ([kernel.kallsyms])
perf 770116 [001] 27981.041375: 1 cycles:P: ffffffff90ee4960 event_function+0xf0 ([kernel.kallsyms])
perf 770116 [001] 27981.041377: 1 cycles:P: ffffffff90c184b1 intel_bts_enable_local+0x31 ([kernel.kallsyms])
perf 770116 [001] 27981.041379: 51611 cycles:P: ffffffff91a160b0 native_sched_clock+0x30 ([kernel.kallsyms])
migration/1 26 [001] 27981.041400: 4227682775 cycles:P: ffffffff90d06a74 wakeup_preempt+0x44 ([kernel.kallsyms])
migration/2 32 [002] 27981.041477: 4159401534 cycles:P: ffffffff90d11993 update_load_avg+0x63 ([kernel.kallsyms])
sshd 708098 [000] 18446744069.414584: 286392 offcpu-time:
79a864f1c8bb ppoll+0x4b (/usr/lib/libc.so.6)
585690935cca [unknown] (/usr/bin/sshd)
```
After:
```
perf 774767 [003] 28178.033444: 497 cycles:P: ffffffff91a160c3 native_sched_clock+0x43 ([kernel.kallsyms])
perf 774767 [003] 28178.033445: 399440 cycles:P: ffffffff91c01f8d nmi_restore+0x25 ([kernel.kallsyms])
swapper 0 [001] 28178.036639: 376650973 cycles:P: ffffffff91a1ae99 intel_idle+0x59 ([kernel.kallsyms])
swapper 0 [003] 28178.182921: 348779378 cycles:P: ffffffff91a1ae99 intel_idle+0x59 ([kernel.kallsyms])
blueman-tray 1355 [000] 28178.627906: 100184571 offcpu-time:
7528eef1c39d __poll+0x4d (/usr/lib/libc.so.6)
7528edf7d8fd [unknown] (/usr/lib/libglib-2.0.so.0.8000.2)
7528edf1af95 g_main_context_iteration+0x35 (/usr/lib/libglib-2.0.so.0.8000.2)
7528eda4ab86 g_application_run+0x1f6 (/usr/lib/libgio-2.0.so.0.8000.2)
7528ee6aa596 [unknown] (/usr/lib/libffi.so.8.1.4)
7fff24e862d8 [unknown] ([unknown])
blueman-tray 1355 [000] 28178.728137: 100187539 offcpu-time:
7528eef1c39d __poll+0x4d (/usr/lib/libc.so.6)
7528edf7d8fd [unknown] (/usr/lib/libglib-2.0.so.0.8000.2)
7528edf1af95 g_main_context_iteration+0x35 (/usr/lib/libglib-2.0.so.0.8000.2)
7528eda4ab86 g_application_run+0x1f6 (/usr/lib/libgio-2.0.so.0.8000.2)
7528ee6aa596 [unknown] (/usr/lib/libffi.so.8.1.4)
7fff24e862d8 [unknown] ([unknown])
swapper 0 [000] 28178.463253: 195945410 cycles:P: ffffffff91a1ae99 intel_idle+0x59 ([kernel.kallsyms])
dbus-broker 412 [002] 28178.464855: 376737008 cycles:P: ffffffff91c000a0 entry_SYSCALL_64+0x20 ([kernel.kallsyms])
```
Howard Chu (9):
perf evsel: Set BPF output to system-wide
perf record --off-cpu: Add --off-cpu-thresh
perf record --off-cpu: Parse offcpu-time event
perf record off-cpu: Dump direct off-cpu samples in BPF
perf record --off-cpu: Dump total off-cpu time at the end.
perf evsel: Delete unnecessary = 0
perf record --off-cpu: Parse BPF output embedded data
perf header: Add field 'embed'
perf test: Add direct off-cpu dumping test
tools/perf/builtin-record.c | 26 ++++
tools/perf/builtin-script.c | 5 +-
tools/perf/tests/builtin-test.c | 1 +
tools/perf/tests/shell/record_offcpu.sh | 27 ++++
tools/perf/tests/tests.h | 1 +
tools/perf/tests/workloads/Build | 1 +
tools/perf/tests/workloads/offcpu.c | 16 +++
tools/perf/util/bpf_off_cpu.c | 176 +++++++++++++++---------
tools/perf/util/bpf_skel/off_cpu.bpf.c | 135 ++++++++++++++++++
tools/perf/util/evsel.c | 49 ++++---
tools/perf/util/evsel.h | 13 ++
tools/perf/util/header.c | 12 ++
tools/perf/util/off_cpu.h | 10 +-
tools/perf/util/record.h | 1 +
tools/perf/util/session.c | 16 ++-
15 files changed, 401 insertions(+), 88 deletions(-)
create mode 100644 tools/perf/tests/workloads/offcpu.c
--
2.45.2
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