159 lines
3.8 KiB
C
159 lines
3.8 KiB
C
/* Copyright (c) 2016 Facebook
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of version 2 of the GNU General Public
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* License as published by the Free Software Foundation.
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*/
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#include <uapi/linux/bpf.h>
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#include <uapi/linux/ptrace.h>
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#include <uapi/linux/perf_event.h>
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#include <linux/version.h>
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#include <linux/sched.h>
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#include <bpf/bpf_helpers.h>
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#include <bpf/bpf_tracing.h>
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#define _(P) \
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({ \
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typeof(P) val; \
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bpf_probe_read_kernel(&val, sizeof(val), &(P)); \
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val; \
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})
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#define MINBLOCK_US 1
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#define MAX_ENTRIES 10000
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struct key_t {
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char waker[TASK_COMM_LEN];
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char target[TASK_COMM_LEN];
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u32 wret;
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u32 tret;
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};
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struct {
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__uint(type, BPF_MAP_TYPE_HASH);
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__type(key, struct key_t);
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__type(value, u64);
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__uint(max_entries, MAX_ENTRIES);
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} counts SEC(".maps");
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struct {
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__uint(type, BPF_MAP_TYPE_HASH);
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__type(key, u32);
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__type(value, u64);
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__uint(max_entries, MAX_ENTRIES);
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} start SEC(".maps");
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struct wokeby_t {
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char name[TASK_COMM_LEN];
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u32 ret;
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};
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struct {
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__uint(type, BPF_MAP_TYPE_HASH);
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__type(key, u32);
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__type(value, struct wokeby_t);
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__uint(max_entries, MAX_ENTRIES);
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} wokeby SEC(".maps");
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struct {
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__uint(type, BPF_MAP_TYPE_STACK_TRACE);
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__uint(key_size, sizeof(u32));
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__uint(value_size, PERF_MAX_STACK_DEPTH * sizeof(u64));
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__uint(max_entries, MAX_ENTRIES);
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} stackmap SEC(".maps");
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#define STACKID_FLAGS (0 | BPF_F_FAST_STACK_CMP)
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SEC("kprobe/try_to_wake_up")
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int waker(struct pt_regs *ctx)
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{
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struct task_struct *p = (void *) PT_REGS_PARM1(ctx);
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struct wokeby_t woke;
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u32 pid;
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pid = _(p->pid);
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bpf_get_current_comm(&woke.name, sizeof(woke.name));
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woke.ret = bpf_get_stackid(ctx, &stackmap, STACKID_FLAGS);
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bpf_map_update_elem(&wokeby, &pid, &woke, BPF_ANY);
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return 0;
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}
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static inline int update_counts(void *ctx, u32 pid, u64 delta)
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{
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struct wokeby_t *woke;
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u64 zero = 0, *val;
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struct key_t key;
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__builtin_memset(&key.waker, 0, sizeof(key.waker));
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bpf_get_current_comm(&key.target, sizeof(key.target));
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key.tret = bpf_get_stackid(ctx, &stackmap, STACKID_FLAGS);
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key.wret = 0;
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woke = bpf_map_lookup_elem(&wokeby, &pid);
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if (woke) {
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key.wret = woke->ret;
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__builtin_memcpy(&key.waker, woke->name, sizeof(key.waker));
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bpf_map_delete_elem(&wokeby, &pid);
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}
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val = bpf_map_lookup_elem(&counts, &key);
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if (!val) {
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bpf_map_update_elem(&counts, &key, &zero, BPF_NOEXIST);
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val = bpf_map_lookup_elem(&counts, &key);
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if (!val)
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return 0;
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}
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(*val) += delta;
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return 0;
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}
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#if 1
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/* taken from /sys/kernel/debug/tracing/events/sched/sched_switch/format */
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struct sched_switch_args {
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unsigned long long pad;
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char prev_comm[TASK_COMM_LEN];
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int prev_pid;
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int prev_prio;
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long long prev_state;
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char next_comm[TASK_COMM_LEN];
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int next_pid;
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int next_prio;
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};
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SEC("tracepoint/sched/sched_switch")
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int oncpu(struct sched_switch_args *ctx)
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{
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/* record previous thread sleep time */
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u32 pid = ctx->prev_pid;
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#else
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SEC("kprobe/finish_task_switch")
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int oncpu(struct pt_regs *ctx)
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{
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struct task_struct *p = (void *) PT_REGS_PARM1(ctx);
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/* record previous thread sleep time */
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u32 pid = _(p->pid);
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#endif
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u64 delta, ts, *tsp;
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ts = bpf_ktime_get_ns();
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bpf_map_update_elem(&start, &pid, &ts, BPF_ANY);
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/* calculate current thread's delta time */
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pid = bpf_get_current_pid_tgid();
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tsp = bpf_map_lookup_elem(&start, &pid);
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if (!tsp)
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/* missed start or filtered */
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return 0;
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delta = bpf_ktime_get_ns() - *tsp;
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bpf_map_delete_elem(&start, &pid);
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delta = delta / 1000;
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if (delta < MINBLOCK_US)
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return 0;
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return update_counts(ctx, pid, delta);
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}
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char _license[] SEC("license") = "GPL";
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u32 _version SEC("version") = LINUX_VERSION_CODE;
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