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Groups > linux.kernel > #1211097
| From | Wang Nan <wangnan0@huawei.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | [PATCH 29/29] bpf: Introduce function for outputing data to perf event |
| Date | 2015-08-21 12:20 +0200 |
| Message-ID | <pZRAw-DT-63@gated-at.bofh.it> (permalink) |
| References | <pZRAt-DT-3@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
From: He Kuang <hekuang@huawei.com>
There're scenarios that we need an eBPF program to record not only
kprobe point args, but also the PMU counters, time latencies or the
number of cache misses between two probe points and other information
when the probe point is entered.
This patch adds a new trace event to establish infrastruction for bpf to
output data to perf. Userspace perf tools can detect and use this event
as using the existing tracepoint events.
New bpf trace event entry in debugfs:
/sys/kernel/debug/tracing/events/bpf/bpf_output_data
Userspace perf tools detect the new tracepoint event as:
bpf:bpf_output_data [Tracepoint event]
Data in ring-buffer of perf events added to this event will be polled
out, sample types and other attributes can be adjusted to those events
directly without touching the original kprobe events.
The bpf helper function gives eBPF program ability to output data as
perf sample event. This helper simple call the new trace event and
userspace perf tools can record the BPF ftrace event to collect those
records.
Signed-off-by: He Kuang <hekuang@huawei.com>
Acked-by: Alexei Starovoitov <ast@plumgrid.com>
---
include/trace/events/bpf.h | 30 ++++++++++++++++++++++++++++++
include/uapi/linux/bpf.h | 7 +++++++
kernel/trace/bpf_trace.c | 23 +++++++++++++++++++++++
samples/bpf/bpf_helpers.h | 2 ++
4 files changed, 62 insertions(+)
create mode 100644 include/trace/events/bpf.h
diff --git a/include/trace/events/bpf.h b/include/trace/events/bpf.h
new file mode 100644
index 0000000..6b739b8
--- /dev/null
+++ b/include/trace/events/bpf.h
@@ -0,0 +1,30 @@
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM bpf
+
+#if !defined(_TRACE_BPF_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_BPF_H
+
+#include <linux/tracepoint.h>
+
+TRACE_EVENT(bpf_output_data,
+
+ TP_PROTO(u64 *src, int size),
+
+ TP_ARGS(src, size),
+
+ TP_STRUCT__entry(
+ __dynamic_array(u8, buf, size)
+ ),
+
+ TP_fast_assign(
+ memcpy(__get_dynamic_array(buf), src, size);
+ ),
+
+ TP_printk("%s", __print_hex(__get_dynamic_array(buf),
+ __get_dynamic_array_len(buf)))
+);
+
+#endif /* _TRACE_BPF_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 29ef6f9..5068ab1 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -249,6 +249,13 @@ enum bpf_func_id {
* Return: 0 on success
*/
BPF_FUNC_get_current_comm,
+
+ /**
+ * int bpf_output_trace_data(void *src, int size)
+ * Return: 0 on success
+ */
+ BPF_FUNC_output_trace_data,
+
__BPF_FUNC_MAX_ID,
};
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 88a041a..219f670 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -11,7 +11,10 @@
#include <linux/filter.h>
#include <linux/uaccess.h>
#include <linux/ctype.h>
+
#include "trace.h"
+#define CREATE_TRACE_POINTS
+#include <trace/events/bpf.h>
static DEFINE_PER_CPU(int, bpf_prog_active);
@@ -79,6 +82,24 @@ static const struct bpf_func_proto bpf_probe_read_proto = {
.arg3_type = ARG_ANYTHING,
};
+static u64 bpf_output_trace_data(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
+{
+ void *src = (void *) (long) r1;
+ int size = (int) r2;
+
+ trace_bpf_output_data(src, size);
+
+ return 0;
+}
+
+static const struct bpf_func_proto bpf_output_trace_data_proto = {
+ .func = bpf_output_trace_data,
+ .gpl_only = true,
+ .ret_type = RET_INTEGER,
+ .arg1_type = ARG_PTR_TO_STACK,
+ .arg2_type = ARG_CONST_STACK_SIZE,
+};
+
/*
* limited trace_printk()
* only %d %u %x %ld %lu %lx %lld %llu %llx %p conversion specifiers allowed
@@ -169,6 +190,8 @@ static const struct bpf_func_proto *kprobe_prog_func_proto(enum bpf_func_id func
return &bpf_map_delete_elem_proto;
case BPF_FUNC_probe_read:
return &bpf_probe_read_proto;
+ case BPF_FUNC_output_trace_data:
+ return &bpf_output_trace_data_proto;
case BPF_FUNC_ktime_get_ns:
return &bpf_ktime_get_ns_proto;
case BPF_FUNC_tail_call:
diff --git a/samples/bpf/bpf_helpers.h b/samples/bpf/bpf_helpers.h
index bdf1c16..0aeaebe 100644
--- a/samples/bpf/bpf_helpers.h
+++ b/samples/bpf/bpf_helpers.h
@@ -59,5 +59,7 @@ static int (*bpf_l3_csum_replace)(void *ctx, int off, int from, int to, int flag
(void *) BPF_FUNC_l3_csum_replace;
static int (*bpf_l4_csum_replace)(void *ctx, int off, int from, int to, int flags) =
(void *) BPF_FUNC_l4_csum_replace;
+static int (*bpf_output_trace_data)(void *src, int size) =
+ (void *) BPF_FUNC_output_trace_data;
#endif
--
2.1.0
--
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[GIT PULL 00/29] perf tools: filtering events using eBPF programs Wang Nan <wangnan0@huawei.com> - 2015-08-21 12:20 +0200
[PATCH 25/29] perf record: Support custom vmlinux path Wang Nan <wangnan0@huawei.com> - 2015-08-21 12:20 +0200
[PATCH 14/29] perf tests: Enforce LLVM test for BPF test Wang Nan <wangnan0@huawei.com> - 2015-08-21 12:20 +0200
[PATCH 18/29] perf probe: Reset args and nargs for probe_trace_event when failure Wang Nan <wangnan0@huawei.com> - 2015-08-21 12:20 +0200
[PATCH 11/29] perf tools: Suppress probing messages when probing by BPF loading Wang Nan <wangnan0@huawei.com> - 2015-08-21 12:20 +0200
[PATCH 13/29] perf tools: Infrastructure for compiling scriptlets when passing '.c' to --event Wang Nan <wangnan0@huawei.com> - 2015-08-21 12:20 +0200
[PATCH 19/29] perf tools: Move linux/filter.h to tools/include Wang Nan <wangnan0@huawei.com> - 2015-08-21 12:20 +0200
[PATCH 05/29] perf probe: Attach trace_probe_event with perf_probe_event Wang Nan <wangnan0@huawei.com> - 2015-08-21 12:20 +0200
[PATCH 21/29] perf tools: Introduce arch_get_reg_info() for x86 Wang Nan <wangnan0@huawei.com> - 2015-08-21 12:20 +0200
[PATCH 03/29] perf ebpf: Add the libbpf glue Wang Nan <wangnan0@huawei.com> - 2015-08-21 12:20 +0200
[PATCH 10/29] perf tools: Attach eBPF program to perf event Wang Nan <wangnan0@huawei.com> - 2015-08-21 12:20 +0200
[PATCH 01/29] perf probe: Try to use symbol table if searching debug info failed Wang Nan <wangnan0@huawei.com> - 2015-08-21 12:20 +0200
Re: [PATCH 01/29] perf probe: Try to use symbol table if searching debug info failed Arnaldo Carvalho de Melo <acme@redhat.com> - 2015-08-21 16:20 +0200
[tip:perf/core] perf probe: Try to use symbol table if searching debug info failed tip-bot for Wang Nan <tipbot@zytor.com> - 2015-08-22 09:00 +0200
[PATCH 16/29] bpf tools: Load a program with different instances using preprocessor Wang Nan <wangnan0@huawei.com> - 2015-08-21 12:20 +0200
[PATCH 07/29] perf bpf: Collect 'struct perf_probe_event' for bpf_program Wang Nan <wangnan0@huawei.com> - 2015-08-21 12:20 +0200
[PATCH 04/29] perf tools: Enable passing bpf object file to --event Wang Nan <wangnan0@huawei.com> - 2015-08-21 12:20 +0200
[PATCH 20/29] perf tools: Add BPF_PROLOGUE config options for further patches Wang Nan <wangnan0@huawei.com> - 2015-08-21 12:20 +0200
[PATCH 24/29] perf tools: Use same BPF program if arguments are identical Wang Nan <wangnan0@huawei.com> - 2015-08-21 12:20 +0200
[PATCH 23/29] perf tools: Generate prologue for BPF programs Wang Nan <wangnan0@huawei.com> - 2015-08-21 12:20 +0200
[PATCH 02/29] perf tools: Make perf depend on libbpf Wang Nan <wangnan0@huawei.com> - 2015-08-21 12:20 +0200
[PATCH 29/29] bpf: Introduce function for outputing data to perf event Wang Nan <wangnan0@huawei.com> - 2015-08-21 12:20 +0200
[PATCH 12/29] perf record: Add clang options for compiling BPF scripts Wang Nan <wangnan0@huawei.com> - 2015-08-21 12:20 +0200
[PATCH 06/29] perf record, bpf: Parse and probe eBPF programs probe points Wang Nan <wangnan0@huawei.com> - 2015-08-21 12:20 +0200
[PATCH 27/29] perf tools: Support attach BPF program on uprobe events Wang Nan <wangnan0@huawei.com> - 2015-08-21 12:20 +0200
[PATCH 17/29] perf tools: Fix probe-event.h include Wang Nan <wangnan0@huawei.com> - 2015-08-21 12:20 +0200
[PATCH 28/29] tools lib traceevent: Support function __get_dynamic_array_len Wang Nan <wangnan0@huawei.com> - 2015-08-21 12:20 +0200
Re: [PATCH 28/29] tools lib traceevent: Support function __get_dynamic_array_len Arnaldo Carvalho de Melo <acme@redhat.com> - 2015-08-21 18:10 +0200
[PATCH 15/29] perf test: Add 'perf test BPF' Wang Nan <wangnan0@huawei.com> - 2015-08-21 12:20 +0200
[PATCH 08/29] perf record: Load all eBPF object into kernel Wang Nan <wangnan0@huawei.com> - 2015-08-21 12:30 +0200
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