perf kwork: Implement BPF trace

'perf record' generates perf.data, which generates extra interrupts
for hard disk, amount of data to be collected increases with time.

Using eBPF trace can process the data in kernel, which solves the
preceding two problems.

Add -b/--use-bpf option for latency and report to support
tracing kwork events using eBPF:

1. Create bpf prog and attach to tracepoints,
2. Start tracing after command is entered,
3. After user hit "ctrl+c", stop tracing and report,
4. Support CPU and name filtering.

This commit implements the framework code and
does not add specific event support.

Test cases:

  # perf kwork rep -h

   Usage: perf kwork report [<options>]

      -b, --use-bpf         Use BPF to measure kwork runtime
      -C, --cpu <cpu>       list of cpus to profile
      -i, --input <file>    input file name
      -n, --name <name>     event name to profile
      -s, --sort <key[,key2...]>
                            sort by key(s): runtime, max, count
      -S, --with-summary    Show summary with statistics
          --time <str>      Time span for analysis (start,stop)

  # perf kwork lat -h

   Usage: perf kwork latency [<options>]

      -b, --use-bpf         Use BPF to measure kwork latency
      -C, --cpu <cpu>       list of cpus to profile
      -i, --input <file>    input file name
      -n, --name <name>     event name to profile
      -s, --sort <key[,key2...]>
                            sort by key(s): avg, max, count
          --time <str>      Time span for analysis (start,stop)

  # perf kwork lat -b
  Unsupported bpf trace class irq

  # perf kwork rep -b
  Unsupported bpf trace class irq

Signed-off-by: Yang Jihong <yangjihong1@huawei.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Clarke <pc@us.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220709015033.38326-15-yangjihong1@huawei.com
[ Simplify work_findnew() ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 74 insertions, 0 deletions

diff --git a/tools/perf/util/bpf_skel/kwork_trace.bpf.c b/tools/perf/util/bpf_skel/kwork_trace.bpf.c
new file mode 100644
index 000000000000..36112be831e3
--- /dev/null
+++ b/tools/perf/util/bpf_skel/kwork_trace.bpf.c
@@ -0,0 +1,74 @@
+// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+// Copyright (c) 2022, Huawei
+
+#include "vmlinux.h"
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+
+#define KWORK_COUNT 100
+#define MAX_KWORKNAME 128
+
+/*
+ * This should be in sync with "util/kwork.h"
+ */
+enum kwork_class_type {
+	KWORK_CLASS_IRQ,
+	KWORK_CLASS_SOFTIRQ,
+	KWORK_CLASS_WORKQUEUE,
+	KWORK_CLASS_MAX,
+};
+
+struct work_key {
+	__u32 type;
+	__u32 cpu;
+	__u64 id;
+};
+
+struct report_data {
+	__u64 nr;
+	__u64 total_time;
+	__u64 max_time;
+	__u64 max_time_start;
+	__u64 max_time_end;
+};
+
+struct {
+	__uint(type, BPF_MAP_TYPE_HASH);
+	__uint(key_size, sizeof(struct work_key));
+	__uint(value_size, MAX_KWORKNAME);
+	__uint(max_entries, KWORK_COUNT);
+} perf_kwork_names SEC(".maps");
+
+struct {
+	__uint(type, BPF_MAP_TYPE_HASH);
+	__uint(key_size, sizeof(struct work_key));
+	__uint(value_size, sizeof(__u64));
+	__uint(max_entries, KWORK_COUNT);
+} perf_kwork_time SEC(".maps");
+
+struct {
+	__uint(type, BPF_MAP_TYPE_HASH);
+	__uint(key_size, sizeof(struct work_key));
+	__uint(value_size, sizeof(struct report_data));
+	__uint(max_entries, KWORK_COUNT);
+} perf_kwork_report SEC(".maps");
+
+struct {
+	__uint(type, BPF_MAP_TYPE_HASH);
+	__uint(key_size, sizeof(__u32));
+	__uint(value_size, sizeof(__u8));
+	__uint(max_entries, 1);
+} perf_kwork_cpu_filter SEC(".maps");
+
+struct {
+	__uint(type, BPF_MAP_TYPE_ARRAY);
+	__uint(key_size, sizeof(__u32));
+	__uint(value_size, MAX_KWORKNAME);
+	__uint(max_entries, 1);
+} perf_kwork_name_filter SEC(".maps");
+
+int enabled = 0;
+int has_cpu_filter = 0;
+int has_name_filter = 0;
+
+char LICENSE[] SEC("license") = "Dual BSD/GPL";