[PATCH RFC 2/2] perf record: Put a copy of kcore into the perf.data directory
From: Adrian Hunter
Date: Mon Sep 16 2019 - 04:58:10 EST
Add a new 'perf record' option '--kcore' which will put a copy of /proc/kcore,
kallsyms and modules into the perf.data directory.
Example:
$ sudo perf record --kcore uname
$ sudo tree perf.data
perf.data
âââ kcore_dir
â âââ kallsyms
â âââ kcore
â âââ modules
âââ perf.data
$ sudo perf script -v
build id event received for vmlinux: 1eaa285996affce2d74d8e66dcea09a80c9941de
build id event received for [vdso]: 8bbaf5dc62a9b644b4d4e4539737e104e4a84541
Samples for 'cycles' event do not have CPU attribute set. Skipping 'cpu' field.
Using CPUID GenuineIntel-6-8E-A
Using perf.data/kcore_dir/kcore for kernel data
Using perf.data/kcore_dir/kallsyms for symbols
perf 19058 506778.423729: 1 cycles: ffffffffa2caa548 native_write_msr+0x8 (vmlinux)
perf 19058 506778.423733: 1 cycles: ffffffffa2caa548 native_write_msr+0x8 (vmlinux)
perf 19058 506778.423734: 7 cycles: ffffffffa2caa548 native_write_msr+0x8 (vmlinux)
perf 19058 506778.423736: 117 cycles: ffffffffa2caa54a native_write_msr+0xa (vmlinux)
perf 19058 506778.423738: 2092 cycles: ffffffffa2c9b7b0 native_apic_msr_write+0x0 (vmlinux)
perf 19058 506778.423740: 37380 cycles: ffffffffa2f121d0 perf_event_addr_filters_exec+0x0 (vmlinux)
uname 19058 506778.423751: 582673 cycles: ffffffffa303a407 propagate_protected_usage+0x147 (vmlinux)
uname 19058 506778.423892: 2241841 cycles: ffffffffa2cae0c9 unwind_next_frame.part.5+0x79 (vmlinux)
uname 19058 506778.424430: 2457397 cycles: ffffffffa3019232 check_memory_region+0x52 (vmlinux)
Signed-off-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
---
tools/perf/Documentation/perf-record.txt | 3 ++
tools/perf/builtin-record.c | 52 ++++++++++++++++++++++++
tools/perf/util/data.c | 33 +++++++++++++++
tools/perf/util/data.h | 2 +
tools/perf/util/record.h | 1 +
tools/perf/util/session.c | 4 ++
tools/perf/util/util.c | 17 ++++++++
7 files changed, 112 insertions(+)
diff --git a/tools/perf/Documentation/perf-record.txt b/tools/perf/Documentation/perf-record.txt
index c6f9f31b6039..1d85e24aa453 100644
--- a/tools/perf/Documentation/perf-record.txt
+++ b/tools/perf/Documentation/perf-record.txt
@@ -571,6 +571,9 @@ config terms. For example: 'cycles/overwrite/' and 'instructions/no-overwrite/'.
Implies --tail-synthesize.
+--kcore::
+Make a copy of /proc/kcore and place it into a directory with the perf.data file.
+
SEE ALSO
--------
linkperf:perf-stat[1], linkperf:perf-list[1]
diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 4c356a046dd3..b665ec7254b9 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -53,6 +53,9 @@
#include <signal.h>
#include <sys/mman.h>
#include <sys/wait.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
#include <linux/string.h>
#include <linux/time64.h>
#include <linux/zalloc.h>
@@ -696,6 +699,37 @@ static int record__auxtrace_init(struct record *rec __maybe_unused)
#endif
+static bool record__kcore_readable(struct machine *machine)
+{
+ char kcore[PATH_MAX];
+ int fd;
+
+ scnprintf(kcore, sizeof(kcore), "%s/proc/kcore", machine->root_dir);
+
+ fd = open(kcore, O_RDONLY);
+ if (fd < 0)
+ return false;
+
+ close(fd);
+
+ return true;
+}
+
+static int record__kcore_copy(struct machine *machine, struct perf_data *data)
+{
+ char from_dir[PATH_MAX];
+ char kcore_dir[PATH_MAX];
+ int ret;
+
+ snprintf(from_dir, sizeof(from_dir), "%s/proc", machine->root_dir);
+
+ ret = perf_data__make_kcore_dir(data, kcore_dir, sizeof(kcore_dir));
+ if (ret)
+ return ret;
+
+ return kcore_copy(from_dir, kcore_dir);
+}
+
static int record__mmap_evlist(struct record *rec,
struct evlist *evlist)
{
@@ -1378,6 +1412,12 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
session->header.env.comp_type = PERF_COMP_ZSTD;
session->header.env.comp_level = rec->opts.comp_level;
+ if (rec->opts.kcore &&
+ !record__kcore_readable(&session->machines.host)) {
+ pr_err("ERROR: kcore is not readable.\n");
+ return -1;
+ }
+
record__init_features(rec);
if (rec->opts.use_clockid && rec->opts.clockid_res_ns)
@@ -1409,6 +1449,14 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
}
session->header.env.comp_mmap_len = session->evlist->mmap_len;
+ if (rec->opts.kcore) {
+ err = record__kcore_copy(&session->machines.host, data);
+ if (err) {
+ pr_err("ERROR: Failed to copy kcore\n");
+ goto out_child;
+ }
+ }
+
err = bpf__apply_obj_config();
if (err) {
char errbuf[BUFSIZ];
@@ -2179,6 +2227,7 @@ static struct option __record_options[] = {
parse_cgroups),
OPT_UINTEGER('D', "delay", &record.opts.initial_delay,
"ms to wait before starting measurement after program start"),
+ OPT_BOOLEAN(0, "kcore", &record.opts.kcore, "copy /proc/kcore"),
OPT_STRING('u', "uid", &record.opts.target.uid_str, "user",
"user to profile"),
@@ -2317,6 +2366,9 @@ int cmd_record(int argc, const char **argv)
}
+ if (rec->opts.kcore)
+ rec->data.is_dir = true;
+
if (rec->opts.comp_level != 0) {
pr_debug("Compression enabled, disabling build id collection at the end of the session.\n");
rec->no_buildid = true;
diff --git a/tools/perf/util/data.c b/tools/perf/util/data.c
index 2fd3114d1167..86b2d6cf5f11 100644
--- a/tools/perf/util/data.c
+++ b/tools/perf/util/data.c
@@ -434,3 +434,36 @@ unsigned long perf_data__size(struct perf_data *data)
return size;
}
+
+int perf_data__make_kcore_dir(struct perf_data *data, char *buf, size_t buf_sz)
+{
+ int ret;
+
+ if (!data->is_dir)
+ return -1;
+
+ ret = snprintf(buf, buf_sz, "%s/kcore_dir", data->path);
+ if (ret < 0 || (size_t)ret >= buf_sz)
+ return -1;
+
+ return mkdir(buf, S_IRWXU);
+}
+
+char *perf_data__kallsyms_name(struct perf_data *data)
+{
+ char *kallsyms_name;
+ struct stat st;
+
+ if (!data->is_dir)
+ return NULL;
+
+ if (asprintf(&kallsyms_name, "%s/kcore_dir/kallsyms", data->path) < 0)
+ return NULL;
+
+ if (stat(kallsyms_name, &st)) {
+ free(kallsyms_name);
+ return NULL;
+ }
+
+ return kallsyms_name;
+}
diff --git a/tools/perf/util/data.h b/tools/perf/util/data.h
index 0c5994d969c7..cb906b524897 100644
--- a/tools/perf/util/data.h
+++ b/tools/perf/util/data.h
@@ -83,4 +83,6 @@ int perf_data__open_dir(struct perf_data *data);
void perf_data__close_dir(struct perf_data *data);
int perf_data__update_dir(struct perf_data *data);
unsigned long perf_data__size(struct perf_data *data);
+int perf_data__make_kcore_dir(struct perf_data *data, char *buf, size_t buf_sz);
+char *perf_data__kallsyms_name(struct perf_data *data);
#endif /* __PERF_DATA_H */
diff --git a/tools/perf/util/record.h b/tools/perf/util/record.h
index 00275afc524d..948bbcf9aef3 100644
--- a/tools/perf/util/record.h
+++ b/tools/perf/util/record.h
@@ -44,6 +44,7 @@ struct record_opts {
bool strict_freq;
bool sample_id;
bool no_bpf_event;
+ bool kcore;
unsigned int freq;
unsigned int mmap_pages;
unsigned int auxtrace_mmap_pages;
diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index 6dd04bd092d1..00d3e75ca1f4 100644
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -224,6 +224,10 @@ struct perf_session *perf_session__new(struct perf_data *data,
/* Open the directory data. */
if (data->is_multi_file && perf_data__open_dir(data))
goto out_delete;
+
+ if (!symbol_conf.kallsyms_name &&
+ !symbol_conf.vmlinux_name)
+ symbol_conf.kallsyms_name = perf_data__kallsyms_name(data);
}
} else {
session->machines.host.env = &perf_env;
diff --git a/tools/perf/util/util.c b/tools/perf/util/util.c
index 5ca7490afdd1..44568ce5082f 100644
--- a/tools/perf/util/util.c
+++ b/tools/perf/util/util.c
@@ -184,6 +184,21 @@ static int rm_rf_depth_pat(const char *path, int depth, const char **pat)
return rmdir(path);
}
+static int rm_rf_kcore_dir(const char *path)
+{
+ char kcore_dir_path[PATH_MAX];
+ const char *pat[] = {
+ "kcore",
+ "kallsyms",
+ "modules",
+ NULL,
+ };
+
+ snprintf(kcore_dir_path, sizeof(kcore_dir_path), "%s/kcore_dir", path);
+
+ return rm_rf_depth_pat(kcore_dir_path, 0, pat);
+}
+
int rm_rf_perf_data(const char *path)
{
const char *pat[] = {
@@ -193,6 +208,8 @@ int rm_rf_perf_data(const char *path)
NULL,
};
+ rm_rf_kcore_dir(path);
+
return rm_rf_depth_pat(path, 0, pat);
}
--
2.17.1