blob: 161edfbc4672b8a33711eb46a2be3c36f10abc14 [file] [log] [blame]
#!/usr/bin/python
# Copyright (c) PLUMgrid, Inc.
# Licensed under the Apache License, Version 2.0 (the "License")
from bcc import BPF
from time import sleep
b = BPF(text="""
#include <uapi/linux/ptrace.h>
#include <linux/sched.h>
struct key_t {
u32 prev_pid;
u32 curr_pid;
};
// map_type, key_type, leaf_type, table_name, num_entry
BPF_HASH(stats, struct key_t, u64, 1024);
int count_sched(struct pt_regs *ctx, struct task_struct *prev) {
struct key_t key = {};
u64 zero = 0, *val;
key.curr_pid = bpf_get_current_pid_tgid();
key.prev_pid = prev->pid;
// could also use `stats.increment(key);`
val = stats.lookup_or_init(&key, &zero);
(*val)++;
return 0;
}
""")
b.attach_kprobe(event="finish_task_switch", fn_name="count_sched")
# generate many schedule events
for i in range(0, 100): sleep(0.01)
for k, v in b["stats"].items():
print("task_switch[%5d->%5d]=%u" % (k.prev_pid, k.curr_pid, v.value))