From 2c3c1048746a4622d8c89a29670120dc8fab93c4 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 20:49:45 +0200 Subject: Adding upstream version 6.1.76. Signed-off-by: Daniel Baumann --- samples/bpf/lathist_kern.c | 99 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 99 insertions(+) create mode 100644 samples/bpf/lathist_kern.c (limited to 'samples/bpf/lathist_kern.c') diff --git a/samples/bpf/lathist_kern.c b/samples/bpf/lathist_kern.c new file mode 100644 index 000000000..4adfcbbe6 --- /dev/null +++ b/samples/bpf/lathist_kern.c @@ -0,0 +1,99 @@ +/* Copyright (c) 2013-2015 PLUMgrid, http://plumgrid.com + * Copyright (c) 2015 BMW Car IT GmbH + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of version 2 of the GNU General Public + * License as published by the Free Software Foundation. + */ +#include +#include +#include +#include + +#define MAX_ENTRIES 20 +#define MAX_CPU 4 + +/* We need to stick to static allocated memory (an array instead of + * hash table) because managing dynamic memory from the + * trace_preempt_[on|off] tracepoints hooks is not supported. + */ + +struct { + __uint(type, BPF_MAP_TYPE_ARRAY); + __type(key, int); + __type(value, u64); + __uint(max_entries, MAX_CPU); +} my_map SEC(".maps"); + +SEC("kprobe/trace_preempt_off") +int bpf_prog1(struct pt_regs *ctx) +{ + int cpu = bpf_get_smp_processor_id(); + u64 *ts = bpf_map_lookup_elem(&my_map, &cpu); + + if (ts) + *ts = bpf_ktime_get_ns(); + + return 0; +} + +static unsigned int log2(unsigned int v) +{ + unsigned int r; + unsigned int shift; + + r = (v > 0xFFFF) << 4; v >>= r; + shift = (v > 0xFF) << 3; v >>= shift; r |= shift; + shift = (v > 0xF) << 2; v >>= shift; r |= shift; + shift = (v > 0x3) << 1; v >>= shift; r |= shift; + r |= (v >> 1); + + return r; +} + +static unsigned int log2l(unsigned long v) +{ + unsigned int hi = v >> 32; + + if (hi) + return log2(hi) + 32; + else + return log2(v); +} + +struct { + __uint(type, BPF_MAP_TYPE_ARRAY); + __type(key, int); + __type(value, long); + __uint(max_entries, MAX_CPU * MAX_ENTRIES); +} my_lat SEC(".maps"); + +SEC("kprobe/trace_preempt_on") +int bpf_prog2(struct pt_regs *ctx) +{ + u64 *ts, cur_ts, delta; + int key, cpu; + long *val; + + cpu = bpf_get_smp_processor_id(); + ts = bpf_map_lookup_elem(&my_map, &cpu); + if (!ts) + return 0; + + cur_ts = bpf_ktime_get_ns(); + delta = log2l(cur_ts - *ts); + + if (delta > MAX_ENTRIES - 1) + delta = MAX_ENTRIES - 1; + + key = cpu * MAX_ENTRIES + delta; + val = bpf_map_lookup_elem(&my_lat, &key); + if (val) + __sync_fetch_and_add((long *)val, 1); + + return 0; + +} + +char _license[] SEC("license") = "GPL"; +u32 _version SEC("version") = LINUX_VERSION_CODE; -- cgit v1.2.3