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38 lines
933 B
38 lines
933 B
#!/usr/bin/env python
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# Copyright (c) PLUMgrid, Inc.
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# Licensed under the Apache License, Version 2.0 (the "License")
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from bcc import BPF
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from time import sleep
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b = BPF(text="""
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#include <uapi/linux/ptrace.h>
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#include <linux/sched.h>
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struct key_t {
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u32 prev_pid;
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u32 curr_pid;
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};
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// map_type, key_type, leaf_type, table_name, num_entry
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BPF_HASH(stats, struct key_t, u64, 1024);
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int count_sched(struct pt_regs *ctx, struct task_struct *prev) {
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struct key_t key = {};
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u64 zero = 0, *val;
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key.curr_pid = bpf_get_current_pid_tgid();
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key.prev_pid = prev->pid;
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// could also use `stats.increment(key);`
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val = stats.lookup_or_init(&key, &zero);
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(*val)++;
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return 0;
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}
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""")
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b.attach_kprobe(event="finish_task_switch", fn_name="count_sched")
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# generate many schedule events
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for i in range(0, 100): sleep(0.01)
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for k, v in b["stats"].items():
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print("task_switch[%5d->%5d]=%u" % (k.prev_pid, k.curr_pid, v.value))
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