[v4,perf,bpf,07/15] perf, bpf: save bpf_prog_info information as headers to perf.data
diff mbox series

Message ID 20190226002019.3748539-8-songliubraving@fb.com
State Changes Requested
Delegated to: BPF Maintainers
Headers show
Series
  • perf annotation of BPF programs
Related show

Commit Message

Song Liu Feb. 26, 2019, 12:20 a.m. UTC
This patch enables perf-record to save bpf_prog_info information as
headers to perf.data. A new header type HEADER_BPF_PROG_INFO is
introduced for this data.

Signed-off-by: Song Liu <songliubraving@fb.com>
---
 tools/perf/util/header.c | 143 ++++++++++++++++++++++++++++++++++++++-
 tools/perf/util/header.h |   1 +
 2 files changed, 143 insertions(+), 1 deletion(-)

Comments

Jiri Olsa Feb. 27, 2019, 1:21 p.m. UTC | #1
On Mon, Feb 25, 2019 at 04:20:11PM -0800, Song Liu wrote:

SNIP

> +		if (info_len > sizeof(struct bpf_prog_info)) {
> +			pr_warning("detected invalid bpf_prog_info\n");
> +			goto out;
> +		}
> +
> +		info_linear = malloc(sizeof(struct bpf_prog_info_linear) +
> +				     data_len);
> +		if (!info_linear)
> +			goto out;
> +		info_linear->info_len = sizeof(struct bpf_prog_info);
> +		info_linear->data_len = data_len;
> +		if (do_read_u64(ff, (u64 *)(&info_linear->arrays)))
> +			goto out;
> +		if (__do_read(ff, &info_linear->info, info_len))
> +			goto out;
> +		if (info_len < sizeof(struct bpf_prog_info))
> +			memset(((void *)(&info_linear->info)) + info_len, 0,
> +			       sizeof(struct bpf_prog_info) - info_len);
> +
> +		if (__do_read(ff, info_linear->data, data_len))
> +			goto out;
> +
> +		/* endian mismatch, drop the info, continue */

so there's no way we can swap the data? why?

jirka

> +		if (ff->ph->needs_swap) {
> +			free(info_linear);
> +			continue;
> +		}

SNIP
Song Liu Feb. 27, 2019, 5:28 p.m. UTC | #2
> On Feb 27, 2019, at 5:21 AM, Jiri Olsa <jolsa@redhat.com> wrote:
> 
> On Mon, Feb 25, 2019 at 04:20:11PM -0800, Song Liu wrote:
> 
> SNIP
> 
>> +		if (info_len > sizeof(struct bpf_prog_info)) {
>> +			pr_warning("detected invalid bpf_prog_info\n");
>> +			goto out;
>> +		}
>> +
>> +		info_linear = malloc(sizeof(struct bpf_prog_info_linear) +
>> +				     data_len);
>> +		if (!info_linear)
>> +			goto out;
>> +		info_linear->info_len = sizeof(struct bpf_prog_info);
>> +		info_linear->data_len = data_len;
>> +		if (do_read_u64(ff, (u64 *)(&info_linear->arrays)))
>> +			goto out;
>> +		if (__do_read(ff, &info_linear->info, info_len))
>> +			goto out;
>> +		if (info_len < sizeof(struct bpf_prog_info))
>> +			memset(((void *)(&info_linear->info)) + info_len, 0,
>> +			       sizeof(struct bpf_prog_info) - info_len);
>> +
>> +		if (__do_read(ff, info_linear->data, data_len))
>> +			goto out;
>> +
>> +		/* endian mismatch, drop the info, continue */
> 
> so there's no way we can swap the data? why?
> 
> jirka

Yes, we can swap the data. OTOH, the set is big enough. How about we 
implement the swap later? Running perf-report on a system of with 
different endianness is a relatively rare case. 

Thanks,
Song



>> +		if (ff->ph->needs_swap) {
>> +			free(info_linear);
>> +			continue;
>> +		}
> 
> SNIP

Patch
diff mbox series

diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index dec6d218c31c..c89dce7942d1 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -18,6 +18,7 @@ 
 #include <sys/utsname.h>
 #include <linux/time64.h>
 #include <dirent.h>
+#include <bpf/libbpf.h>
 
 #include "evlist.h"
 #include "evsel.h"
@@ -39,6 +40,7 @@ 
 #include "tool.h"
 #include "time-utils.h"
 #include "units.h"
+#include "bpf-event.h"
 
 #include "sane_ctype.h"
 
@@ -1080,6 +1082,51 @@  static int write_clockid(struct feat_fd *ff,
 			sizeof(ff->ph->env.clockid_res_ns));
 }
 
+static int write_bpf_prog_info(struct feat_fd *ff,
+			       struct perf_evlist *evlist __maybe_unused)
+{
+	struct perf_env *env = &ff->ph->env;
+	struct rb_root *root;
+	struct rb_node *next;
+	u32 count = 0;
+	int ret;
+
+	down_read(&env->bpf_progs.lock);
+
+	root = &env->bpf_progs.prog_infos;
+	next = rb_first(root);
+	while (next) {
+		++count;
+		next = rb_next(next);
+	}
+
+	ret = do_write(ff, &count, sizeof(count));
+
+	if (ret < 0)
+		goto out;
+
+	next = rb_first(root);
+	while (next) {
+		struct bpf_prog_info_node *node;
+		size_t len;
+
+		node = rb_entry(next, struct bpf_prog_info_node, rb_node);
+		next = rb_next(&node->rb_node);
+		len = sizeof(struct bpf_prog_info_linear) +
+			node->info_linear->data_len;
+
+		/* before writing to file, translate address to offset */
+		bpf_program__bpil_addr_to_offs(node->info_linear);
+		ret = do_write(ff, node->info_linear, len);
+		bpf_program__bpil_offs_to_addr(node->info_linear);
+		if (ret < 0)
+			goto out;
+	}
+out:
+	up_read(&env->bpf_progs.lock);
+	return ret;
+}
+
 static int cpu_cache_level__sort(const void *a, const void *b)
 {
 	struct cpu_cache_level *cache_a = (struct cpu_cache_level *)a;
@@ -1560,6 +1607,29 @@  static void print_clockid(struct feat_fd *ff, FILE *fp)
 		ff->ph->env.clockid_res_ns * 1000);
 }
 
+static void print_bpf_prog_info(struct feat_fd *ff, FILE *fp)
+{
+	struct perf_env *env = &ff->ph->env;
+	struct rb_root *root;
+	struct rb_node *next;
+
+	down_read(&env->bpf_progs.lock);
+
+	root = &env->bpf_progs.prog_infos;
+	next = rb_first(root);
+
+	while (next) {
+		struct bpf_prog_info_node *node;
+
+		node = rb_entry(next, struct bpf_prog_info_node, rb_node);
+		next = rb_next(&node->rb_node);
+		fprintf(fp, "# bpf_prog_info of id %u\n",
+			node->info_linear->info.id);
+	}
+
+	up_read(&env->bpf_progs.lock);
+}
+
 static void free_event_desc(struct perf_evsel *events)
 {
 	struct perf_evsel *evsel;
@@ -2592,6 +2662,76 @@  static int process_clockid(struct feat_fd *ff,
 	return 0;
 }
 
+static int process_bpf_prog_info(struct feat_fd *ff,
+				 void *data __maybe_unused)
+{
+	struct bpf_prog_info_linear *info_linear;
+	struct bpf_prog_info_node *info_node;
+	struct perf_env *env = &ff->ph->env;
+	u32 count, i;
+	int err = -1;
+
+	if (do_read_u32(ff, &count))
+		return -1;
+
+	down_write(&env->bpf_progs.lock);
+
+	for (i = 0; i < count; ++i) {
+		u32 info_len, data_len;
+
+		info_linear = NULL;
+		info_node = NULL;
+		if (do_read_u32(ff, &info_len))
+			goto out;
+		if (do_read_u32(ff, &data_len))
+			goto out;
+
+		if (info_len > sizeof(struct bpf_prog_info)) {
+			pr_warning("detected invalid bpf_prog_info\n");
+			goto out;
+		}
+
+		info_linear = malloc(sizeof(struct bpf_prog_info_linear) +
+				     data_len);
+		if (!info_linear)
+			goto out;
+		info_linear->info_len = sizeof(struct bpf_prog_info);
+		info_linear->data_len = data_len;
+		if (do_read_u64(ff, (u64 *)(&info_linear->arrays)))
+			goto out;
+		if (__do_read(ff, &info_linear->info, info_len))
+			goto out;
+		if (info_len < sizeof(struct bpf_prog_info))
+			memset(((void *)(&info_linear->info)) + info_len, 0,
+			       sizeof(struct bpf_prog_info) - info_len);
+
+		if (__do_read(ff, info_linear->data, data_len))
+			goto out;
+
+		/* endian mismatch, drop the info, continue */
+		if (ff->ph->needs_swap) {
+			free(info_linear);
+			continue;
+		}
+
+		info_node = malloc(sizeof(struct bpf_prog_info_node));
+		if (!info_node)
+			goto out;
+
+		/* after reading from file, translate offset to address */
+		bpf_program__bpil_offs_to_addr(info_linear);
+		info_node->info_linear = info_linear;
+		perf_env__insert_bpf_prog_info(env, info_node);
+	}
+
+	return 0;
+out:
+	free(info_linear);
+	free(info_node);
+	up_write(&env->bpf_progs.lock);
+	return err;
+}
+
 struct feature_ops {
 	int (*write)(struct feat_fd *ff, struct perf_evlist *evlist);
 	void (*print)(struct feat_fd *ff, FILE *fp);
@@ -2651,7 +2791,8 @@  static const struct feature_ops feat_ops[HEADER_LAST_FEATURE] = {
 	FEAT_OPN(CACHE,		cache,		true),
 	FEAT_OPR(SAMPLE_TIME,	sample_time,	false),
 	FEAT_OPR(MEM_TOPOLOGY,	mem_topology,	true),
-	FEAT_OPR(CLOCKID,       clockid,        false)
+	FEAT_OPR(CLOCKID,       clockid,        false),
+	FEAT_OPR(BPF_PROG_INFO, bpf_prog_info,  false)
 };
 
 struct header_print_data {
diff --git a/tools/perf/util/header.h b/tools/perf/util/header.h
index 0d553ddca0a3..0785c91b4c3a 100644
--- a/tools/perf/util/header.h
+++ b/tools/perf/util/header.h
@@ -39,6 +39,7 @@  enum {
 	HEADER_SAMPLE_TIME,
 	HEADER_MEM_TOPOLOGY,
 	HEADER_CLOCKID,
+	HEADER_BPF_PROG_INFO,
 	HEADER_LAST_FEATURE,
 	HEADER_FEAT_BITS	= 256,
 };