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Message-Id: <20250718-perf_aux_pause_resume_bpf_rebase-v2-3-992557b8fb16@arm.com>
Date: Fri, 18 Jul 2025 16:25:37 +0100
From: Leo Yan <leo.yan@....com>
To: Peter Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...hat.com>,
Arnaldo Carvalho de Melo <acme@...nel.org>,
Namhyung Kim <namhyung@...nel.org>, Jiri Olsa <jolsa@...nel.org>,
Ian Rogers <irogers@...gle.com>, Adrian Hunter <adrian.hunter@...el.com>,
KP Singh <kpsingh@...nel.org>, Matt Bobrowski <mattbobrowski@...gle.com>,
Song Liu <song@...nel.org>, Alexei Starovoitov <ast@...nel.org>,
Daniel Borkmann <daniel@...earbox.net>, Andrii Nakryiko <andrii@...nel.org>,
Martin KaFai Lau <martin.lau@...ux.dev>,
Eduard Zingerman <eddyz87@...il.com>,
Yonghong Song <yonghong.song@...ux.dev>,
John Fastabend <john.fastabend@...il.com>,
Stanislav Fomichev <sdf@...ichev.me>, Hao Luo <haoluo@...gle.com>,
Steven Rostedt <rostedt@...dmis.org>,
Masami Hiramatsu <mhiramat@...nel.org>,
Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
James Clark <james.clark@...aro.org>,
Suzuki K Poulose <suzuki.poulose@....com>,
Mike Leach <mike.leach@...aro.org>
Cc: linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org,
bpf@...r.kernel.org, linux-trace-kernel@...r.kernel.org,
Leo Yan <leo.yan@....com>
Subject: [PATCH PATCH v2 v2 3/6] perf: auxtrace: Control AUX pause and
resume with BPF
Introduce a BPF program to trigger AUX pause and resume.
Once a attached tracepoint is hit, the BPF program calls the
bpf_perf_event_aux_pause() kfunc for controlling AUX trace.
Signed-off-by: Leo Yan <leo.yan@....com>
---
tools/perf/Makefile.perf | 1 +
tools/perf/util/bpf_skel/auxtrace_pause.bpf.c | 156 ++++++++++++++++++++++++++
2 files changed, 157 insertions(+)
diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf
index d4c7031b01a77f4a42326e4c9a88d8a352143178..8fdd24ba4c25ff4a69925a8e0c85bc78dd4fda47 100644
--- a/tools/perf/Makefile.perf
+++ b/tools/perf/Makefile.perf
@@ -1179,6 +1179,7 @@ SKELETONS += $(SKEL_OUT)/kwork_trace.skel.h $(SKEL_OUT)/sample_filter.skel.h
SKELETONS += $(SKEL_OUT)/kwork_top.skel.h $(SKEL_OUT)/syscall_summary.skel.h
SKELETONS += $(SKEL_OUT)/bench_uprobe.skel.h
SKELETONS += $(SKEL_OUT)/augmented_raw_syscalls.skel.h
+SKELETONS += $(SKEL_OUT)/auxtrace_pause.skel.h
$(SKEL_TMP_OUT) $(LIBAPI_OUTPUT) $(LIBBPF_OUTPUT) $(LIBPERF_OUTPUT) $(LIBSUBCMD_OUTPUT) $(LIBSYMBOL_OUTPUT):
$(Q)$(MKDIR) -p $@
diff --git a/tools/perf/util/bpf_skel/auxtrace_pause.bpf.c b/tools/perf/util/bpf_skel/auxtrace_pause.bpf.c
new file mode 100644
index 0000000000000000000000000000000000000000..2752651dbb6013401b568175b61183e2ac0e7f98
--- /dev/null
+++ b/tools/perf/util/bpf_skel/auxtrace_pause.bpf.c
@@ -0,0 +1,156 @@
+// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+// Copyright 2025 Arm Limited
+#include "vmlinux.h"
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+
+struct {
+ __uint(type, BPF_MAP_TYPE_HASH);
+ __uint(key_size, sizeof(__u32));
+ __uint(value_size, sizeof(__u8));
+ __uint(max_entries, 1);
+} cpu_filter SEC(".maps");
+
+struct {
+ __uint(type, BPF_MAP_TYPE_HASH);
+ __uint(key_size, sizeof(__u32));
+ __uint(value_size, sizeof(__u8));
+ __uint(max_entries, 1);
+} task_filter SEC(".maps");
+
+struct {
+ __uint(type, BPF_MAP_TYPE_PERF_EVENT_ARRAY);
+ __uint(key_size, sizeof(__u32));
+ __uint(value_size, sizeof(int));
+ __uint(max_entries, 1);
+} events SEC(".maps");
+
+int enabled = 0;
+
+const volatile int has_cpu = 0;
+const volatile int has_task = 0;
+const volatile int per_thread = 0;
+
+int bpf_perf_event_aux_pause(void *map, u64 flags, u32 pause) __ksym;
+
+static int event_aux_pause(void)
+{
+ __u64 flag;
+ __u32 cpu = bpf_get_smp_processor_id();
+
+ if (!enabled)
+ return 0;
+
+ if (has_cpu) {
+ __u8 *ok;
+
+ ok = bpf_map_lookup_elem(&cpu_filter, &cpu);
+ if (!ok)
+ return 0;
+ }
+
+ if (has_task) {
+ __u32 pid = bpf_get_current_pid_tgid() & 0xffffffff;
+ __u8 *ok;
+
+ ok = bpf_map_lookup_elem(&task_filter, &pid);
+ if (!ok)
+ return 0;
+ }
+
+ flag = per_thread ? 0 : BPF_F_CURRENT_CPU;
+ bpf_perf_event_aux_pause(&events, flag, 1);
+ return 0;
+}
+
+static int event_aux_resume(void)
+{
+ __u64 flag;
+ __u32 cpu = bpf_get_smp_processor_id();
+
+ if (!enabled)
+ return 0;
+
+ if (has_cpu) {
+ __u8 *ok;
+
+ ok = bpf_map_lookup_elem(&cpu_filter, &cpu);
+ if (!ok)
+ return 0;
+ }
+
+ if (has_task) {
+ __u32 pid = bpf_get_current_pid_tgid() & 0xffffffff;
+ __u8 *ok;
+
+ ok = bpf_map_lookup_elem(&task_filter, &pid);
+ if (!ok)
+ return 0;
+ }
+
+ flag = per_thread ? 0 : BPF_F_CURRENT_CPU;
+ bpf_perf_event_aux_pause(&events, flag, 0);
+ return 0;
+}
+
+SEC("kprobe/func_pause")
+int BPF_PROG(kprobe_event_pause)
+{
+ return event_aux_pause();
+}
+
+SEC("kprobe/func_resume")
+int BPF_PROG(kprobe_event_resume)
+{
+ return event_aux_resume();
+}
+
+SEC("kretprobe/func_pause")
+int BPF_PROG(kretprobe_event_pause)
+{
+ return event_aux_pause();
+}
+
+SEC("kretprobe/func_resume")
+int BPF_PROG(kretprobe_event_resume)
+{
+ return event_aux_resume();
+}
+
+SEC("uprobe/func_pause")
+int BPF_PROG(uprobe_event_pause)
+{
+ return event_aux_pause();
+}
+
+SEC("uprobe/func_resume")
+int BPF_PROG(uprobe_event_resume)
+{
+ return event_aux_resume();
+}
+
+SEC("uretprobe/func_pause")
+int BPF_PROG(uretprobe_event_pause)
+{
+ return event_aux_pause();
+}
+
+SEC("uretprobe/func_resume")
+int BPF_PROG(uretprobe_event_resume)
+{
+ return event_aux_resume();
+}
+
+SEC("tp/func_pause")
+int BPF_PROG(tp_event_pause)
+{
+ return event_aux_pause();
+}
+
+SEC("tp/func_resume")
+int BPF_PROG(tp_event_resume)
+{
+ return event_aux_resume();
+}
+
+char LICENSE[] SEC("license") = "Dual BSD/GPL";
--
2.34.1
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