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https://github.com/brain-hackers/linux-brain.git
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1c47910ef8
The bpf program is called 50 times a second and does hashmap[kern&user_stackid]++ It's primary purpose to check that key bpf helpers like map lookup, update, get_stackid, trace_printk and ctx access are all working. It checks: - PERF_COUNT_HW_CPU_CYCLES on all cpus - PERF_COUNT_HW_CPU_CYCLES for current process and inherited perf_events to children - PERF_COUNT_SW_CPU_CLOCK on all cpus - PERF_COUNT_SW_CPU_CLOCK for current process Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
66 lines
1.7 KiB
C
66 lines
1.7 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 <linux/ptrace.h>
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#include <linux/version.h>
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#include <uapi/linux/bpf.h>
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#include <uapi/linux/bpf_perf_event.h>
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#include <uapi/linux/perf_event.h>
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#include "bpf_helpers.h"
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struct key_t {
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char comm[TASK_COMM_LEN];
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u32 kernstack;
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u32 userstack;
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};
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struct bpf_map_def SEC("maps") counts = {
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.type = BPF_MAP_TYPE_HASH,
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.key_size = sizeof(struct key_t),
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.value_size = sizeof(u64),
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.max_entries = 10000,
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};
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struct bpf_map_def SEC("maps") stackmap = {
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.type = BPF_MAP_TYPE_STACK_TRACE,
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.key_size = sizeof(u32),
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.value_size = PERF_MAX_STACK_DEPTH * sizeof(u64),
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.max_entries = 10000,
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};
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#define KERN_STACKID_FLAGS (0 | BPF_F_FAST_STACK_CMP)
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#define USER_STACKID_FLAGS (0 | BPF_F_FAST_STACK_CMP | BPF_F_USER_STACK)
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SEC("perf_event")
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int bpf_prog1(struct bpf_perf_event_data *ctx)
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{
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char fmt[] = "CPU-%d period %lld ip %llx";
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u32 cpu = bpf_get_smp_processor_id();
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struct key_t key;
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u64 *val, one = 1;
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if (ctx->sample_period < 10000)
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/* ignore warmup */
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return 0;
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bpf_get_current_comm(&key.comm, sizeof(key.comm));
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key.kernstack = bpf_get_stackid(ctx, &stackmap, KERN_STACKID_FLAGS);
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key.userstack = bpf_get_stackid(ctx, &stackmap, USER_STACKID_FLAGS);
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if ((int)key.kernstack < 0 && (int)key.userstack < 0) {
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bpf_trace_printk(fmt, sizeof(fmt), cpu, ctx->sample_period,
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ctx->regs.ip);
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return 0;
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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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(*val)++;
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else
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bpf_map_update_elem(&counts, &key, &one, BPF_NOEXIST);
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return 0;
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}
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char _license[] SEC("license") = "GPL";
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