Commit eeb399b5 authored by Adrian Hunter's avatar Adrian Hunter Committed by Arnaldo Carvalho de Melo
Browse files

perf record: Put a copy of kcore into the perf.data directory 



Add a new 'perf record' option '--kcore' which will put a copy of
/proc/kcore, kallsyms and modules into a perf.data directory. Note, that
without the --kcore option, output goes to a file as previously.  The
tools' -o and -i options work with either a file name or directory name.

Example:

  $ sudo perf record --kcore uname

  $ sudo tree perf.data
  perf.data
  ├── kcore_dir
  │   ├── kallsyms
  │   ├── kcore
  │   └── modules
  └── 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)

Committer testing:

  # rm -rf perf.data*
  # perf record sleep 1
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.024 MB perf.data (7 samples) ]
  # ls -l perf.data
  -rw-------. 1 root root 34772 Oct 21 11:08 perf.data
  # perf record --kcore uname
  Linux
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.024 MB perf.data (7 samples) ]
  ls[root@quaco ~]# ls -lad perf.data*
  drwx------. 3 root root  4096 Oct 21 11:08 perf.data
  -rw-------. 1 root root 34772 Oct 21 11:08 perf.data.old
  # perf evlist -v
  cycles: size: 112, { sample_period, sample_freq }: 4000, sample_type: IP|TID|TIME|PERIOD, read_format: ID, disabled: 1, inherit: 1, mmap: 1, comm: 1, freq: 1, enable_on_exec: 1, task: 1, precise_ip: 3, sample_id_all: 1, exclude_guest: 1, mmap2: 1, comm_exec: 1, ksymbol: 1, bpf_event: 1
  # perf evlist -v -i perf.data/data
  cycles: size: 112, { sample_period, sample_freq }: 4000, sample_type: IP|TID|TIME|PERIOD, read_format: ID, disabled: 1, inherit: 1, mmap: 1, comm: 1, freq: 1, enable_on_exec: 1, task: 1, precise_ip: 3, sample_id_all: 1, exclude_guest: 1, mmap2: 1, comm_exec: 1, ksymbol: 1, bpf_event: 1
  #

Signed-off-by: default avatarAdrian Hunter <adrian.hunter@intel.com>
Reviewed-by: default avatarJiri Olsa <jolsa@kernel.org>
Tested-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
Link: http://lore.kernel.org/lkml/20191004083121.12182-6-adrian.hunter@intel.com


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 46e201ef

tools/perf/Documentation/perf-record.txt

+3 −0
Original line number Diff line number Diff line
@@ -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]

tools/perf/Documentation/perf.data-directory-format.txt

+35 −0
Original line number Diff line number Diff line
@@ -26,3 +26,38 @@ The current only version value 0 means that: 


Future versions are expected to describe different data files

layout according to special needs.



Currently the only 'perf record' option to output to a directory is

the --kcore option which puts a copy of /proc/kcore into the directory.

e.g.



  $ sudo perf record --kcore uname

  Linux

  [ perf record: Woken up 1 times to write data ]

  [ perf record: Captured and wrote 0.015 MB perf.data (9 samples) ]

  $ sudo tree -ps perf.data

  perf.data

  ├── [-rw-------       23744]  data

  └── [drwx------        4096]  kcore_dir

      ├── [-r--------     6731125]  kallsyms

      ├── [-r--------    40230912]  kcore

      └── [-r--------        5419]  modules



  1 directory, 4 files

  $ sudo perf script -v

  build id event received for vmlinux: 1eaa285996affce2d74d8e66dcea09a80c9941de

  build id event received for [vdso]: 8bbaf5dc62a9b644b4d4e4539737e104e4a84541

  build id event received for /lib/x86_64-linux-gnu/libc-2.28.so: 5b157f49586a3ca84d55837f97ff466767dd3445

  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 15316 2060795.480902:          1 cycles:  ffffffffa2caa548 native_write_msr+0x8 (vmlinux)

              perf 15316 2060795.480906:          1 cycles:  ffffffffa2caa548 native_write_msr+0x8 (vmlinux)

              perf 15316 2060795.480908:          7 cycles:  ffffffffa2caa548 native_write_msr+0x8 (vmlinux)

              perf 15316 2060795.480910:        119 cycles:  ffffffffa2caa54a native_write_msr+0xa (vmlinux)

              perf 15316 2060795.480912:       2109 cycles:  ffffffffa2c9b7b0 native_apic_msr_write+0x0 (vmlinux)

              perf 15316 2060795.480914:      37606 cycles:  ffffffffa2f121fe perf_event_addr_filters_exec+0x2e (vmlinux)

             uname 15316 2060795.480924:     588287 cycles:  ffffffffa303a56d page_counter_try_charge+0x6d (vmlinux)

             uname 15316 2060795.481067:    2261945 cycles:  ffffffffa301438f kmem_cache_free+0x4f (vmlinux)

             uname 15316 2060795.481643:    2172167 cycles:      7f1a48c393c0 _IO_un_link+0x0 (/lib/x86_64-linux-gnu/libc-2.28.so)

tools/perf/builtin-record.c

+52 −0
Original line number Diff line number Diff line
@@ -55,6 +55,9 @@ 
#include <signal.h>

#include <sys/mman.h>

#include <sys/wait.h>

#include <sys/types.h>

#include <sys/stat.h>

#include <fcntl.h>

#include <linux/err.h>

#include <linux/string.h>

#include <linux/time64.h>
@@ -699,6 +702,37 @@ 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)

{
@@ -1383,6 +1417,12 @@ 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)
@@ -1414,6 +1454,14 @@ static int __cmd_record(struct record *rec, int argc, const char **argv) 
	}

	session->header.env.comp_mmap_len = session->evlist->core.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];
@@ -2184,6 +2232,7 @@ 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"),
@@ -2322,6 +2371,9 @@ 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;

tools/perf/util/data.c

+33 −0
Original line number Diff line number Diff line
@@ -424,3 +424,36 @@ 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;

}

tools/perf/util/data.h

+2 −0
Original line number Diff line number Diff line
@@ -87,4 +87,6 @@ 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 */

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