diff options
Diffstat (limited to 'samples/bpf')
| -rw-r--r-- | samples/bpf/Makefile | 4 | ||||
| -rw-r--r-- | samples/bpf/tracex3_kern.c | 89 | ||||
| -rw-r--r-- | samples/bpf/tracex3_user.c | 150 |
3 files changed, 243 insertions, 0 deletions
diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile index 6dd272143733..dcd850546d52 100644 --- a/samples/bpf/Makefile +++ b/samples/bpf/Makefile @@ -8,6 +8,7 @@ hostprogs-y += sockex1 hostprogs-y += sockex2 hostprogs-y += tracex1 hostprogs-y += tracex2 +hostprogs-y += tracex3 test_verifier-objs := test_verifier.o libbpf.o test_maps-objs := test_maps.o libbpf.o @@ -16,6 +17,7 @@ sockex1-objs := bpf_load.o libbpf.o sockex1_user.o sockex2-objs := bpf_load.o libbpf.o sockex2_user.o tracex1-objs := bpf_load.o libbpf.o tracex1_user.o tracex2-objs := bpf_load.o libbpf.o tracex2_user.o +tracex3-objs := bpf_load.o libbpf.o tracex3_user.o # Tell kbuild to always build the programs always := $(hostprogs-y) @@ -23,6 +25,7 @@ always += sockex1_kern.o always += sockex2_kern.o always += tracex1_kern.o always += tracex2_kern.o +always += tracex3_kern.o HOSTCFLAGS += -I$(objtree)/usr/include @@ -31,6 +34,7 @@ HOSTLOADLIBES_sockex1 += -lelf HOSTLOADLIBES_sockex2 += -lelf HOSTLOADLIBES_tracex1 += -lelf HOSTLOADLIBES_tracex2 += -lelf +HOSTLOADLIBES_tracex3 += -lelf # point this to your LLVM backend with bpf support LLC=$(srctree)/tools/bpf/llvm/bld/Debug+Asserts/bin/llc diff --git a/samples/bpf/tracex3_kern.c b/samples/bpf/tracex3_kern.c new file mode 100644 index 000000000000..255ff2792366 --- /dev/null +++ b/samples/bpf/tracex3_kern.c @@ -0,0 +1,89 @@ +/* Copyright (c) 2013-2015 PLUMgrid, http://plumgrid.com + * + * 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 <linux/skbuff.h> +#include <linux/netdevice.h> +#include <linux/version.h> +#include <uapi/linux/bpf.h> +#include "bpf_helpers.h" + +struct bpf_map_def SEC("maps") my_map = { + .type = BPF_MAP_TYPE_HASH, + .key_size = sizeof(long), + .value_size = sizeof(u64), + .max_entries = 4096, +}; + +/* kprobe is NOT a stable ABI. If kernel internals change this bpf+kprobe + * example will no longer be meaningful + */ +SEC("kprobe/blk_mq_start_request") +int bpf_prog1(struct pt_regs *ctx) +{ + long rq = ctx->di; + u64 val = bpf_ktime_get_ns(); + + bpf_map_update_elem(&my_map, &rq, &val, BPF_ANY); + return 0; +} + +static unsigned int log2l(unsigned long long n) +{ +#define S(k) if (n >= (1ull << k)) { i += k; n >>= k; } + int i = -(n == 0); + S(32); S(16); S(8); S(4); S(2); S(1); + return i; +#undef S +} + +#define SLOTS 100 + +struct bpf_map_def SEC("maps") lat_map = { + .type = BPF_MAP_TYPE_ARRAY, + .key_size = sizeof(u32), + .value_size = sizeof(u64), + .max_entries = SLOTS, +}; + +SEC("kprobe/blk_update_request") +int bpf_prog2(struct pt_regs *ctx) +{ + long rq = ctx->di; + u64 *value, l, base; + u32 index; + + value = bpf_map_lookup_elem(&my_map, &rq); + if (!value) + return 0; + + u64 cur_time = bpf_ktime_get_ns(); + u64 delta = cur_time - *value; + + bpf_map_delete_elem(&my_map, &rq); + + /* the lines below are computing index = log10(delta)*10 + * using integer arithmetic + * index = 29 ~ 1 usec + * index = 59 ~ 1 msec + * index = 89 ~ 1 sec + * index = 99 ~ 10sec or more + * log10(x)*10 = log2(x)*10/log2(10) = log2(x)*3 + */ + l = log2l(delta); + base = 1ll << l; + index = (l * 64 + (delta - base) * 64 / base) * 3 / 64; + + if (index >= SLOTS) + index = SLOTS - 1; + + value = bpf_map_lookup_elem(&lat_map, &index); + if (value) + __sync_fetch_and_add((long *)value, 1); + + return 0; +} +char _license[] SEC("license") = "GPL"; +u32 _version SEC("version") = LINUX_VERSION_CODE; diff --git a/samples/bpf/tracex3_user.c b/samples/bpf/tracex3_user.c new file mode 100644 index 000000000000..0aaa933ab938 --- /dev/null +++ b/samples/bpf/tracex3_user.c @@ -0,0 +1,150 @@ +/* Copyright (c) 2013-2015 PLUMgrid, http://plumgrid.com + * + * 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 <stdio.h> +#include <stdlib.h> +#include <signal.h> +#include <unistd.h> +#include <stdbool.h> +#include <string.h> +#include <linux/bpf.h> +#include "libbpf.h" +#include "bpf_load.h" + +#define ARRAY_SIZE(x) (sizeof(x) / sizeof(*(x))) + +#define SLOTS 100 + +static void clear_stats(int fd) +{ + __u32 key; + __u64 value = 0; + + for (key = 0; key < SLOTS; key++) + bpf_update_elem(fd, &key, &value, BPF_ANY); +} + +const char *color[] = { + "\033[48;5;255m", + "\033[48;5;252m", + "\033[48;5;250m", + "\033[48;5;248m", + "\033[48;5;246m", + "\033[48;5;244m", + "\033[48;5;242m", + "\033[48;5;240m", + "\033[48;5;238m", + "\033[48;5;236m", + "\033[48;5;234m", + "\033[48;5;232m", +}; +const int num_colors = ARRAY_SIZE(color); + +const char nocolor[] = "\033[00m"; + +const char *sym[] = { + " ", + " ", + ".", + ".", + "*", + "*", + "o", + "o", + "O", + "O", + "#", + "#", +}; + +bool full_range = false; +bool text_only = false; + +static void print_banner(void) +{ + if (full_range) + printf("|1ns |10ns |100ns |1us |10us |100us" + " |1ms |10ms |100ms |1s |10s\n"); + else + printf("|1us |10us |100us |1ms |10ms " + "|100ms |1s |10s\n"); +} + +static void print_hist(int fd) +{ + __u32 key; + __u64 value; + __u64 cnt[SLOTS]; + __u64 max_cnt = 0; + __u64 total_events = 0; + + for (key = 0; key < SLOTS; key++) { + value = 0; + bpf_lookup_elem(fd, &key, &value); + cnt[key] = value; + total_events += value; + if (value > max_cnt) + max_cnt = value; + } + clear_stats(fd); + for (key = full_range ? 0 : 29; key < SLOTS; key++) { + int c = num_colors * cnt[key] / (max_cnt + 1); + + if (text_only) + printf("%s", sym[c]); + else + printf("%s %s", color[c], nocolor); + } + printf(" # %lld\n", total_events); +} + +int main(int ac, char **argv) +{ + char filename[256]; + int i; + + snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]); + + if (load_bpf_file(filename)) { + printf("%s", bpf_log_buf); + return 1; + } + + for (i = 1; i < ac; i++) { + if (strcmp(argv[i], "-a") == 0) { + full_range = true; + } else if (strcmp(argv[i], "-t") == 0) { + text_only = true; + } else if (strcmp(argv[i], "-h") == 0) { + printf("Usage:\n" + " -a display wider latency range\n" + " -t text only\n"); + return 1; + } + } + + printf(" heatmap of IO latency\n"); + if (text_only) + printf(" %s", sym[num_colors - 1]); + else + printf(" %s %s", color[num_colors - 1], nocolor); + printf(" - many events with this latency\n"); + + if (text_only) + printf(" %s", sym[0]); + else + printf(" %s %s", color[0], nocolor); + printf(" - few events\n"); + + for (i = 0; ; i++) { + if (i % 20 == 0) + print_banner(); + print_hist(map_fd[1]); + sleep(2); + } + + return 0; +} |
