samples/bpf: tracepoint example
modify offwaketime to work with sched/sched_switch tracepoint
instead of kprobe into finish_task_switch
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/samples/bpf/offwaketime_kern.c b/samples/bpf/offwaketime_kern.c
index c0aa5a9..983629a 100644
--- a/samples/bpf/offwaketime_kern.c
+++ b/samples/bpf/offwaketime_kern.c
@@ -73,7 +73,7 @@
return 0;
}
-static inline int update_counts(struct pt_regs *ctx, u32 pid, u64 delta)
+static inline int update_counts(void *ctx, u32 pid, u64 delta)
{
struct key_t key = {};
struct wokeby_t *woke;
@@ -100,15 +100,33 @@
return 0;
}
+#if 1
+/* taken from /sys/kernel/debug/tracing/events/sched/sched_switch/format */
+struct sched_switch_args {
+ unsigned long long pad;
+ char prev_comm[16];
+ int prev_pid;
+ int prev_prio;
+ long long prev_state;
+ char next_comm[16];
+ int next_pid;
+ int next_prio;
+};
+SEC("tracepoint/sched/sched_switch")
+int oncpu(struct sched_switch_args *ctx)
+{
+ /* record previous thread sleep time */
+ u32 pid = ctx->prev_pid;
+#else
SEC("kprobe/finish_task_switch")
int oncpu(struct pt_regs *ctx)
{
struct task_struct *p = (void *) PT_REGS_PARM1(ctx);
- u64 delta, ts, *tsp;
- u32 pid;
-
/* record previous thread sleep time */
- pid = _(p->pid);
+ u32 pid = _(p->pid);
+#endif
+ u64 delta, ts, *tsp;
+
ts = bpf_ktime_get_ns();
bpf_map_update_elem(&start, &pid, &ts, BPF_ANY);