Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762032AbbBJDrw (ORCPT ); Mon, 9 Feb 2015 22:47:52 -0500 Received: from mail-pd0-f172.google.com ([209.85.192.172]:40644 "EHLO mail-pd0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761842AbbBJDqR (ORCPT ); Mon, 9 Feb 2015 22:46:17 -0500 From: Alexei Starovoitov To: Steven Rostedt Cc: Ingo Molnar , Namhyung Kim , Arnaldo Carvalho de Melo , Jiri Olsa , Masami Hiramatsu , linux-api@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v3 linux-trace 5/8] samples: bpf: counting example for kfree_skb tracepoint and write syscall Date: Mon, 9 Feb 2015 19:45:58 -0800 Message-Id: <1423539961-21792-6-git-send-email-ast@plumgrid.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1423539961-21792-1-git-send-email-ast@plumgrid.com> References: <1423539961-21792-1-git-send-email-ast@plumgrid.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7240 Lines: 263 this example has two probes in one C file that attach to different tracepoints and use two different maps. 1st probe is the similar to dropmon.c. It attaches to kfree_skb tracepoint and count number of packet drops at different locations 2nd probe attaches to syscalls/sys_enter_write and computes a histogram of different write sizes Usage: $ sudo tracex2 location 0xffffffff816959a5 count 1 location 0xffffffff816959a5 count 2 557145+0 records in 557145+0 records out 285258240 bytes (285 MB) copied, 1.02379 s, 279 MB/s syscall write() stats byte_size : count distribution 1 -> 1 : 3 | | 2 -> 3 : 0 | | 4 -> 7 : 0 | | 8 -> 15 : 0 | | 16 -> 31 : 2 | | 32 -> 63 : 3 | | 64 -> 127 : 1 | | 128 -> 255 : 1 | | 256 -> 511 : 0 | | 512 -> 1023 : 1118968 |************************************* | Ctrl-C at any time. Kernel will auto cleanup maps and programs Signed-off-by: Alexei Starovoitov --- samples/bpf/Makefile | 4 ++ samples/bpf/tracex2_kern.c | 71 +++++++++++++++++++++++++++++++++ samples/bpf/tracex2_user.c | 95 ++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 170 insertions(+) create mode 100644 samples/bpf/tracex2_kern.c create mode 100644 samples/bpf/tracex2_user.c diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile index da28e1b6d3a6..416af24b01fd 100644 --- a/samples/bpf/Makefile +++ b/samples/bpf/Makefile @@ -8,6 +8,7 @@ hostprogs-y += sockex1 hostprogs-y += sockex2 hostprogs-y += dropmon hostprogs-y += tracex1 +hostprogs-y += tracex2 dropmon-objs := dropmon.o libbpf.o test_verifier-objs := test_verifier.o libbpf.o @@ -16,12 +17,14 @@ sock_example-objs := sock_example.o libbpf.o 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 # Tell kbuild to always build the programs always := $(hostprogs-y) always += sockex1_kern.o always += sockex2_kern.o always += tracex1_kern.o +always += tracex2_kern.o HOSTCFLAGS += -I$(objtree)/usr/include @@ -29,6 +32,7 @@ HOSTCFLAGS_bpf_load.o += -I$(objtree)/usr/include -Wno-unused-variable HOSTLOADLIBES_sockex1 += -lelf HOSTLOADLIBES_sockex2 += -lelf HOSTLOADLIBES_tracex1 += -lelf +HOSTLOADLIBES_tracex2 += -lelf # point this to your LLVM backend with bpf support LLC=$(srctree)/tools/bpf/llvm/bld/Debug+Asserts/bin/llc diff --git a/samples/bpf/tracex2_kern.c b/samples/bpf/tracex2_kern.c new file mode 100644 index 000000000000..a789c456c1b4 --- /dev/null +++ b/samples/bpf/tracex2_kern.c @@ -0,0 +1,71 @@ +#include +#include +#include +#include +#include "bpf_helpers.h" + +struct bpf_map_def SEC("maps") my_map = { + .type = BPF_MAP_TYPE_HASH, + .key_size = sizeof(long), + .value_size = sizeof(long), + .max_entries = 1024, +}; + +SEC("events/skb/kfree_skb") +int bpf_prog2(struct bpf_context *ctx) +{ + long loc = ctx->arg2; + long init_val = 1; + long *value; + + value = bpf_map_lookup_elem(&my_map, &loc); + if (value) + *value += 1; + else + bpf_map_update_elem(&my_map, &loc, &init_val, BPF_ANY); + 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 bpf_map_def SEC("maps") my_hist_map = { + .type = BPF_MAP_TYPE_ARRAY, + .key_size = sizeof(u32), + .value_size = sizeof(long), + .max_entries = 64, +}; + +SEC("events/syscalls/sys_enter_write") +int bpf_prog3(struct bpf_context *ctx) +{ + long write_size = ctx->arg3; + long init_val = 1; + long *value; + u32 index = log2l(write_size); + + value = bpf_map_lookup_elem(&my_hist_map, &index); + if (value) + __sync_fetch_and_add(value, 1); + return 0; +} +char _license[] SEC("license") = "GPL"; diff --git a/samples/bpf/tracex2_user.c b/samples/bpf/tracex2_user.c new file mode 100644 index 000000000000..91b8d0896fbb --- /dev/null +++ b/samples/bpf/tracex2_user.c @@ -0,0 +1,95 @@ +#include +#include +#include +#include +#include +#include "libbpf.h" +#include "bpf_load.h" + +#define MAX_INDEX 64 +#define MAX_STARS 38 + +static void stars(char *str, long val, long max, int width) +{ + int i; + + for (i = 0; i < (width * val / max) - 1 && i < width - 1; i++) + str[i] = '*'; + if (val > max) + str[i - 1] = '+'; + str[i] = '\0'; +} + +static void print_hist(int fd) +{ + int key; + long value; + long data[MAX_INDEX] = {}; + char starstr[MAX_STARS]; + int i; + int max_ind = -1; + long max_value = 0; + + for (key = 0; key < MAX_INDEX; key++) { + bpf_lookup_elem(fd, &key, &value); + data[key] = value; + if (value && key > max_ind) + max_ind = key; + if (value > max_value) + max_value = value; + } + + printf(" syscall write() stats\n"); + printf(" byte_size : count distribution\n"); + for (i = 1; i <= max_ind + 1; i++) { + stars(starstr, data[i - 1], max_value, MAX_STARS); + printf("%8ld -> %-8ld : %-8ld |%-*s|\n", + (1l << i) >> 1, (1l << i) - 1, data[i - 1], + MAX_STARS, starstr); + } +} +static void int_exit(int sig) +{ + print_hist(map_fd[1]); + exit(0); +} + +int main(int ac, char **argv) +{ + char filename[256]; + long key, next_key, value; + FILE *f; + int i; + + snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]); + + signal(SIGINT, int_exit); + + /* start 'ping' in the background to have some kfree_skb events */ + f = popen("ping -c5 localhost", "r"); + (void) f; + + /* start 'dd' in the background to have plenty of 'write' syscalls */ + f = popen("dd if=/dev/zero of=/dev/null count=5000000", "r"); + (void) f; + + if (load_bpf_file(filename)) { + printf("%s", bpf_log_buf); + return 1; + } + + for (i = 0; i < 5; i++) { + key = 0; + while (bpf_get_next_key(map_fd[0], &key, &next_key) == 0) { + bpf_lookup_elem(map_fd[0], &next_key, &value); + printf("location 0x%lx count %ld\n", next_key, value); + key = next_key; + } + if (key) + printf("\n"); + sleep(1); + } + print_hist(map_fd[1]); + + return 0; +} -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/