From: Alexei Starovoitov <ast@plumgrid.com>
To: "David S. Miller" <davem@davemloft.net>
Cc: Ingo Molnar <mingo@kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Andy Lutomirski <luto@amacapital.net>,
Steven Rostedt <rostedt@goodmis.org>,
Daniel Borkmann <dborkman@redhat.com>,
Chema Gonzalez <chema@google.com>,
Eric Dumazet <edumazet@google.com>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Brendan Gregg <brendan.d.gregg@gmail.com>,
Namhyung Kim <namhyung@kernel.org>,
"H. Peter Anvin" <hpa@zytor.com>,
Andrew Morton <akpm@linux-foundation.org>,
Kees Cook <keescook@chromium.org>,
linux-api@vger.kernel.org, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: [PATCH v5 net-next 28/29] samples: bpf: counting eBPF example in C
Date: Sun, 24 Aug 2014 13:21:29 -0700 [thread overview]
Message-ID: <1408911690-7598-29-git-send-email-ast@plumgrid.com> (raw)
In-Reply-To: <1408911690-7598-1-git-send-email-ast@plumgrid.com>
this example has two probes in C that 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 kprobe/sys_write and computes a histogram of different
write sizes
Usage:
$ sudo ex2
Should see:
writing bpf-5 -> /sys/kernel/debug/tracing/events/skb/kfree_skb/filter
writing bpf-8 -> /sys/kernel/debug/tracing/events/kprobes/sys_write/filter
location 0xffffffff816efc67 count 1
location 0xffffffff815d8030 count 1
location 0xffffffff816efc67 count 3
location 0xffffffff815d8030 count 4
location 0xffffffff816efc67 count 9
syscall write() stats
byte_size : count distribution
1 -> 1 : 3141 |**** |
2 -> 3 : 2 | |
4 -> 7 : 14 | |
8 -> 15 : 3268 |***** |
16 -> 31 : 732 | |
32 -> 63 : 20042 |************************************* |
64 -> 127 : 12154 |********************** |
128 -> 255 : 2215 |*** |
256 -> 511 : 9 | |
512 -> 1023 : 0 | |
1024 -> 2047 : 1 | |
Ctrl-C at any time. Kernel will auto cleanup maps and programs
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
---
samples/bpf/Makefile | 6 ++--
samples/bpf/ex2_kern.c | 73 +++++++++++++++++++++++++++++++++++++
samples/bpf/ex2_user.c | 94 ++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 171 insertions(+), 2 deletions(-)
create mode 100644 samples/bpf/ex2_kern.c
create mode 100644 samples/bpf/ex2_user.c
diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
index 7ce9e6b0d3d0..d2de86188925 100644
--- a/samples/bpf/Makefile
+++ b/samples/bpf/Makefile
@@ -2,19 +2,21 @@
obj- := dummy.o
# List of programs to build
-hostprogs-y := dropmon test_verifier ex1
+hostprogs-y := dropmon test_verifier ex1 ex2
dropmon-objs := dropmon.o libbpf.o
test_verifier-objs := test_verifier.o libbpf.o
ex1-objs := bpf_load.o libbpf.o ex1_user.o
+ex2-objs := bpf_load.o libbpf.o ex2_user.o
# Tell kbuild to always build the programs
-always := $(hostprogs-y) ex1_kern.o
+always := $(hostprogs-y) ex1_kern.o ex2_kern.o
HOSTCFLAGS += -I$(objtree)/usr/include
HOSTCFLAGS_bpf_load.o += -I$(objtree)/usr/include -Wno-unused-variable
HOSTLOADLIBES_ex1 += -lelf
+HOSTLOADLIBES_ex2 += -lelf
LLC=$(srctree)/tools/bpf/llvm/bld/Debug+Asserts/bin/llc
diff --git a/samples/bpf/ex2_kern.c b/samples/bpf/ex2_kern.c
new file mode 100644
index 000000000000..2daa50b27ce5
--- /dev/null
+++ b/samples/bpf/ex2_kern.c
@@ -0,0 +1,73 @@
+#include <linux/skbuff.h>
+#include <linux/netdevice.h>
+#include <uapi/linux/bpf.h>
+#include <trace/bpf_trace.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(long),
+ .max_entries = 1024,
+};
+
+SEC("events/skb/kfree_skb")
+int bpf_prog2(struct bpf_context *ctx)
+{
+ long loc = ctx->arg2;
+ long init_val = 1;
+ void *value;
+
+ value = bpf_map_lookup_elem(&my_map, &loc);
+ if (value)
+ (*(long *) value) += 1;
+ else
+ bpf_map_update_elem(&my_map, &loc, &init_val);
+ 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_HASH,
+ .key_size = sizeof(u32),
+ .value_size = sizeof(long),
+ .max_entries = 64,
+};
+
+SEC("events/kprobes/sys_write")
+int bpf_prog3(struct bpf_context *ctx)
+{
+ long write_size = ctx->arg3;
+ long init_val = 1;
+ void *value;
+ u32 index = log2l(write_size);
+
+ value = bpf_map_lookup_elem(&my_hist_map, &index);
+ if (value)
+ __sync_fetch_and_add((long *)value, 1);
+ else
+ bpf_map_update_elem(&my_hist_map, &index, &init_val);
+ return 0;
+}
+char license[] SEC("license") = "GPL";
diff --git a/samples/bpf/ex2_user.c b/samples/bpf/ex2_user.c
new file mode 100644
index 000000000000..fd5ce21ae60a
--- /dev/null
+++ b/samples/bpf/ex2_user.c
@@ -0,0 +1,94 @@
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <signal.h>
+#include <linux/bpf.h>
+#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, next_key;
+ long value;
+ long data[MAX_INDEX] = {};
+ char starstr[MAX_STARS];
+ int i;
+ int max_ind = -1;
+ long max_value = 0;
+
+ key = -1; /* some unknown key */
+ while (bpf_get_next_key(fd, &key, &next_key) == 0) {
+ bpf_lookup_elem(fd, &next_key, &value);
+ if (next_key > MAX_INDEX) {
+ printf("BUG: invalid index %d\n", next_key);
+ } else {
+ data[next_key] = value;
+ if (next_key > max_ind)
+ max_ind = next_key;
+ if (value > max_value)
+ max_value = value;
+ }
+ key = next_key;
+ }
+
+ 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;
+ int i;
+
+ snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
+
+ signal(SIGINT, int_exit);
+
+ i = system("echo 'p:sys_write sys_write' > /sys/kernel/debug/tracing/kprobe_events");
+
+ 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
next prev parent reply other threads:[~2014-08-24 20:23 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-08-24 20:21 [PATCH v5 net-next 00/29] BPF syscall, maps, verifier, samples, llvm Alexei Starovoitov
2014-08-24 20:21 ` [PATCH v5 net-next 01/29] bpf: x86: add missing 'shift by register' instructions to x64 eBPF JIT Alexei Starovoitov
2014-08-24 20:21 ` [PATCH v5 net-next 02/29] net: filter: add "load 64-bit immediate" eBPF instruction Alexei Starovoitov
2014-08-24 20:21 ` [PATCH v5 net-next 03/29] net: filter: split filter.h and expose eBPF to user space Alexei Starovoitov
2014-08-24 20:21 ` [PATCH v5 net-next 04/29] bpf: introduce syscall(BPF, ...) and BPF maps Alexei Starovoitov
2014-08-24 20:21 ` [PATCH v5 net-next 05/29] bpf: enable bpf syscall on x64 and i386 Alexei Starovoitov
2014-08-24 20:21 ` [PATCH v5 net-next 06/29] bpf: add lookup/update/delete/iterate methods to BPF maps Alexei Starovoitov
2014-08-25 21:33 ` Cong Wang
2014-08-25 22:07 ` Alexei Starovoitov
2014-08-24 20:21 ` [PATCH v5 net-next 07/29] bpf: add hashtable type of " Alexei Starovoitov
2014-08-24 20:21 ` [PATCH v5 net-next 08/29] bpf: expand BPF syscall with program load/unload Alexei Starovoitov
2014-08-24 20:21 ` [PATCH v5 net-next 09/29] bpf: handle pseudo BPF_CALL insn Alexei Starovoitov
2014-08-24 20:21 ` [PATCH v5 net-next 10/29] bpf: verifier (add docs) Alexei Starovoitov
2014-08-24 20:21 ` [PATCH v5 net-next 11/29] bpf: verifier (add ability to receive verification log) Alexei Starovoitov
2014-08-24 20:21 ` [PATCH v5 net-next 12/29] bpf: handle pseudo BPF_LD_IMM64 insn Alexei Starovoitov
2014-08-24 20:21 ` [PATCH v5 net-next 13/29] bpf: verifier (add branch/goto checks) Alexei Starovoitov
2014-08-24 20:21 ` [PATCH v5 net-next 14/29] bpf: verifier (add verifier core) Alexei Starovoitov
2014-08-24 20:21 ` [PATCH v5 net-next 15/29] bpf: verifier (add state prunning optimization) Alexei Starovoitov
2014-08-24 20:21 ` [PATCH v5 net-next 16/29] bpf: allow eBPF programs to use maps Alexei Starovoitov
2014-08-24 20:21 ` [PATCH v5 net-next 17/29] bpf: split eBPF out of NET Alexei Starovoitov
2014-08-24 20:21 ` [PATCH v5 net-next 18/29] tracing: allow eBPF programs to be attached to events Alexei Starovoitov
2014-08-24 20:21 ` [PATCH v5 net-next 19/29] tracing: allow eBPF programs call printk() Alexei Starovoitov
2014-08-24 20:21 ` [PATCH v5 net-next 20/29] tracing: allow eBPF programs to be attached to kprobe/kretprobe Alexei Starovoitov
2014-08-24 20:21 ` [PATCH v5 net-next 21/29] tracing: allow eBPF programs to call ktime_get_ns() and get_current() Alexei Starovoitov
2014-08-24 20:21 ` [PATCH v5 net-next 22/29] samples: bpf: add mini eBPF library to manipulate maps and programs Alexei Starovoitov
2014-08-24 20:21 ` [PATCH v5 net-next 23/29] samples: bpf: example of tracing filters with eBPF Alexei Starovoitov
2014-08-24 20:21 ` [PATCH v5 net-next 24/29] bpf: verifier test Alexei Starovoitov
2014-08-24 20:21 ` [PATCH v5 net-next 25/29] bpf: llvm backend Alexei Starovoitov
2014-08-24 20:21 ` [PATCH v5 net-next 26/29] samples: bpf: elf file loader Alexei Starovoitov
2014-08-24 20:21 ` [PATCH v5 net-next 27/29] samples: bpf: eBPF example in C Alexei Starovoitov
2014-08-24 20:21 ` Alexei Starovoitov [this message]
2014-08-24 20:21 ` [PATCH v5 net-next 29/29] samples: bpf: IO latency analysis (iosnoop/heatmap) Alexei Starovoitov
2014-08-25 0:39 ` [PATCH v5 net-next 00/29] BPF syscall, maps, verifier, samples, llvm David Miller
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