41e9a8046c
$ trace_event tests attaching BPF program to HW_CPU_CYCLES, SW_CPU_CLOCK, HW_CACHE_L1D and other events. It runs 'dd' in the background while bpf program collects user and kernel stack trace on counter overflow. User space expects to see sys_read and sys_write in the kernel stack. $ tracex6 tests reading of various perf counters from BPF program. Both tests were refactored to increase coverage and be more accurate. Signed-off-by: Teng Qin <qinteng@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
42 lines
912 B
C
42 lines
912 B
C
#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 "bpf_helpers.h"
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struct bpf_map_def SEC("maps") counters = {
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.type = BPF_MAP_TYPE_PERF_EVENT_ARRAY,
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.key_size = sizeof(int),
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.value_size = sizeof(u32),
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.max_entries = 64,
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};
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struct bpf_map_def SEC("maps") values = {
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.type = BPF_MAP_TYPE_HASH,
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.key_size = sizeof(int),
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.value_size = sizeof(u64),
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.max_entries = 64,
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};
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SEC("kprobe/htab_map_get_next_key")
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int bpf_prog1(struct pt_regs *ctx)
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{
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u32 key = bpf_get_smp_processor_id();
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u64 count, *val;
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s64 error;
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count = bpf_perf_event_read(&counters, key);
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error = (s64)count;
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if (error <= -2 && error >= -22)
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return 0;
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val = bpf_map_lookup_elem(&values, &key);
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if (val)
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*val = count;
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else
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bpf_map_update_elem(&values, &key, &count, 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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u32 _version SEC("version") = LINUX_VERSION_CODE;
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