100 lines
2.2 KiB
C
100 lines
2.2 KiB
C
// SPDX-License-Identifier: GPL-2.0
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// Copyright (c) 2020 Wenbo Zhang
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#include <vmlinux.h>
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#include <bpf/bpf_helpers.h>
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#include <bpf/bpf_core_read.h>
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#include <bpf/bpf_tracing.h>
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#include "cpudist.h"
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#include "bits.bpf.h"
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#include "core_fixes.bpf.h"
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#define TASK_RUNNING 0
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const volatile bool targ_per_process = false;
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const volatile bool targ_per_thread = false;
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const volatile bool targ_offcpu = false;
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const volatile bool targ_ms = false;
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const volatile pid_t targ_tgid = -1;
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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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} start SEC(".maps");
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static struct hist initial_hist;
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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 hist);
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} hists SEC(".maps");
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static __always_inline void store_start(u32 tgid, u32 pid, u64 ts)
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{
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if (targ_tgid != -1 && targ_tgid != tgid)
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return;
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bpf_map_update_elem(&start, &pid, &ts, 0);
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}
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static __always_inline void update_hist(struct task_struct *task,
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u32 tgid, u32 pid, u64 ts)
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{
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u64 delta, *tsp, slot;
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struct hist *histp;
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u32 id;
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if (targ_tgid != -1 && targ_tgid != tgid)
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return;
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tsp = bpf_map_lookup_elem(&start, &pid);
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if (!tsp || ts < *tsp)
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return;
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if (targ_per_process)
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id = tgid;
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else if (targ_per_thread)
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id = pid;
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else
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id = -1;
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histp = bpf_map_lookup_elem(&hists, &id);
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if (!histp) {
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bpf_map_update_elem(&hists, &id, &initial_hist, 0);
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histp = bpf_map_lookup_elem(&hists, &id);
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if (!histp)
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return;
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bpf_probe_read_kernel_str(&histp->comm, sizeof(task->comm),
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task->comm);
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}
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delta = ts - *tsp;
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if (targ_ms)
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delta /= 1000000;
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else
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delta /= 1000;
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slot = log2l(delta);
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if (slot >= MAX_SLOTS)
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slot = MAX_SLOTS - 1;
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__sync_fetch_and_add(&histp->slots[slot], 1);
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}
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SEC("tp_btf/sched_switch")
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int BPF_PROG(sched_switch, bool preempt, struct task_struct *prev,
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struct task_struct *next)
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{
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u32 prev_tgid = prev->tgid, prev_pid = prev->pid;
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u32 tgid = next->tgid, pid = next->pid;
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u64 ts = bpf_ktime_get_ns();
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if (targ_offcpu) {
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store_start(prev_tgid, prev_pid, ts);
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update_hist(next, tgid, pid, ts);
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} else {
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if (get_task_state(prev) == TASK_RUNNING)
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update_hist(prev, prev_tgid, prev_pid, ts);
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store_start(tgid, pid, ts);
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}
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return 0;
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}
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char LICENSE[] SEC("license") = "GPL";
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