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Commit 3c9b1644 authored by Alexei Starovoitov's avatar Alexei Starovoitov Committed by David S. Miller
Browse files

samples/bpf: tracepoint example 



modify offwaketime to work with sched/sched_switch tracepoint
instead of kprobe into finish_task_switch

Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent c0766040

samples/bpf/offwaketime_kern.c

+22 −4
Original line number Diff line number Diff line
@@ -73,7 +73,7 @@ int waker(struct pt_regs *ctx) 
	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 @@ static inline int update_counts(struct pt_regs *ctx, u32 pid, u64 delta) 
	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);

	/* record previous thread sleep time */

	u32 pid = _(p->pid);

#endif

	u64 delta, ts, *tsp;

	u32 pid;



	/* record previous thread sleep time */

	pid = _(p->pid);

	ts = bpf_ktime_get_ns();

	bpf_map_update_elem(&start, &pid, &ts, BPF_ANY);