Re: [PATCH 3/5] perf inject: Keep some features sections from input file

[Adrian Hunter <adrian.hunter@intel.com>]

On 23/05/22 11:14, Jiri Olsa wrote:
> On Fri, May 20, 2022 at 04:24:02PM +0300, Adrian Hunter wrote:
>> perf inject overwrites feature sections with information from the current
>> machine. It makes more sense to keep original information that describes
>> the machine or software when perf record was run.
>>
>> Example: perf.data from "Desktop" injected on "nuc11"
>>
>>  Before:
>>
>>   $ perf script --header-only -i perf.data-from-desktop | head -15
>>   # ========
>>   # captured on    : Thu May 19 09:55:50 2022
>>   # header version : 1
>>   # data offset    : 1208
>>   # data size      : 837480
>>   # feat offset    : 838688
>>   # hostname : Desktop
>>   # os release : 5.13.0-41-generic
>>   # perf version : 5.18.rc5.gac837f7ca7ed
>>   # arch : x86_64
>>   # nrcpus online : 28
>>   # nrcpus avail : 28
>>   # cpudesc : Intel(R) Core(TM) i9-9940X CPU @ 3.30GHz
>>   # cpuid : GenuineIntel,6,85,4
>>   # total memory : 65548656 kB
>>
>>   $ perf inject -i perf.data-from-desktop -o injected-perf.data
>>
>>   $ perf script --header-only -i injected-perf.data | head -15
>>   # ========
>>   # captured on    : Fri May 20 15:06:55 2022
>>   # header version : 1
>>   # data offset    : 1208
>>   # data size      : 837480
>>   # feat offset    : 838688
>>   # hostname : nuc11
>>   # os release : 5.17.5-local
>>   # perf version : 5.18.rc5.g0f828fdeb9af
>>   # arch : x86_64
>>   # nrcpus online : 8
>>   # nrcpus avail : 8
>>   # cpudesc : 11th Gen Intel(R) Core(TM) i7-1165G7 @ 2.80GHz
>>   # cpuid : GenuineIntel,6,140,1
>>   # total memory : 16012124 kB
>>
>>  After:
>>
>>   $ perf inject -i perf.data-from-desktop -o injected-perf.data
>>
>>   $ perf script --header-only -i injected-perf.data | head -15
>>   # ========
>>   # captured on    : Fri May 20 15:08:54 2022
> 
> too bad date is not in separate feature right?

True.  I'd also like to have both the original and new cmdline.

> 
> jirka
> 
>>   # header version : 1
>>   # data offset    : 1208
>>   # data size      : 837480
>>   # feat offset    : 838688
>>   # hostname : Desktop
>>   # os release : 5.13.0-41-generic
>>   # perf version : 5.18.rc5.gac837f7ca7ed
>>   # arch : x86_64
>>   # nrcpus online : 28
>>   # nrcpus avail : 28
>>   # cpudesc : Intel(R) Core(TM) i9-9940X CPU @ 3.30GHz
>>   # cpuid : GenuineIntel,6,85,4
>>   # total memory : 65548656 kB
>>
>> Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
>> ---
>>  tools/perf/builtin-inject.c | 129 +++++++++++++++++++++++++++++++++++-
>>  tools/perf/util/header.c    |   8 +++
>>  tools/perf/util/header.h    |   5 ++
>>  3 files changed, 141 insertions(+), 1 deletion(-)
>>
>> diff --git a/tools/perf/builtin-inject.c b/tools/perf/builtin-inject.c
>> index 5b50a4abf95f..71b6eafe4c19 100644
>> --- a/tools/perf/builtin-inject.c
>> +++ b/tools/perf/builtin-inject.c
>> @@ -27,6 +27,8 @@
>>  #include "util/namespaces.h"
>>  #include "util/util.h"
>>  
>> +#include <internal/lib.h>
>> +
>>  #include <linux/err.h>
>>  #include <subcmd/parse-options.h>
>>  #include <uapi/linux/mman.h> /* To get things like MAP_HUGETLB even on older libc headers */
>> @@ -55,6 +57,7 @@ struct perf_inject {
>>  	struct list_head	samples;
>>  	struct itrace_synth_opts itrace_synth_opts;
>>  	char			event_copy[PERF_SAMPLE_MAX_SIZE];
>> +	struct perf_file_section secs[HEADER_FEAT_BITS];
>>  };
>>  
>>  struct event_entry {
>> @@ -763,6 +766,120 @@ static int parse_vm_time_correlation(const struct option *opt, const char *str,
>>  	return inject->itrace_synth_opts.vm_tm_corr_args ? 0 : -ENOMEM;
>>  }
>>  
>> +static int save_section_info_cb(struct perf_file_section *section,
>> +				struct perf_header *ph __maybe_unused,
>> +				int feat, int fd __maybe_unused, void *data)
>> +{
>> +	struct perf_inject *inject = data;
>> +
>> +	inject->secs[feat] = *section;
>> +	return 0;
>> +}
>> +
>> +static int save_section_info(struct perf_inject *inject)
>> +{
>> +	struct perf_header *header = &inject->session->header;
>> +	int fd = perf_data__fd(inject->session->data);
>> +
>> +	return perf_header__process_sections(header, fd, inject, save_section_info_cb);
>> +}
>> +
>> +static bool keep_feat(int feat)
>> +{
>> +	switch (feat) {
>> +	/* Keep original information that describes the machine or software */
>> +	case HEADER_TRACING_DATA:
>> +	case HEADER_HOSTNAME:
>> +	case HEADER_OSRELEASE:
>> +	case HEADER_VERSION:
>> +	case HEADER_ARCH:
>> +	case HEADER_NRCPUS:
>> +	case HEADER_CPUDESC:
>> +	case HEADER_CPUID:
>> +	case HEADER_TOTAL_MEM:
>> +	case HEADER_CPU_TOPOLOGY:
>> +	case HEADER_NUMA_TOPOLOGY:
>> +	case HEADER_PMU_MAPPINGS:
>> +	case HEADER_CACHE:
>> +	case HEADER_MEM_TOPOLOGY:
>> +	case HEADER_CLOCKID:
>> +	case HEADER_BPF_PROG_INFO:
>> +	case HEADER_BPF_BTF:
>> +	case HEADER_CPU_PMU_CAPS:
>> +	case HEADER_CLOCK_DATA:
>> +	case HEADER_HYBRID_TOPOLOGY:
>> +	case HEADER_HYBRID_CPU_PMU_CAPS:
>> +		return true;
>> +	/* Information that can be updated */
>> +	case HEADER_BUILD_ID:
>> +	case HEADER_CMDLINE:
>> +	case HEADER_EVENT_DESC:
>> +	case HEADER_BRANCH_STACK:
>> +	case HEADER_GROUP_DESC:
>> +	case HEADER_AUXTRACE:
>> +	case HEADER_STAT:
>> +	case HEADER_SAMPLE_TIME:
>> +	case HEADER_DIR_FORMAT:
>> +	case HEADER_COMPRESSED:
>> +	default:
>> +		return false;
>> +	};
>> +}
>> +
>> +static int read_file(int fd, u64 offs, void *buf, size_t sz)
>> +{
>> +	ssize_t ret = preadn(fd, buf, sz, offs);
>> +
>> +	if (ret < 0)
>> +		return -errno;
>> +	if ((size_t)ret != sz)
>> +		return -EINVAL;
>> +	return 0;
>> +}
>> +
>> +static int feat_copy(struct perf_inject *inject, int feat, struct feat_writer *fw)
>> +{
>> +	int fd = perf_data__fd(inject->session->data);
>> +	u64 offs = inject->secs[feat].offset;
>> +	size_t sz = inject->secs[feat].size;
>> +	void *buf = malloc(sz);
>> +	int ret;
>> +
>> +	if (!buf)
>> +		return -ENOMEM;
>> +
>> +	ret = read_file(fd, offs, buf, sz);
>> +	if (ret)
>> +		goto out_free;
>> +
>> +	ret = fw->write(fw, buf, sz);
>> +out_free:
>> +	free(buf);
>> +	return ret;
>> +}
>> +
>> +struct inject_fc {
>> +	struct feat_copier fc;
>> +	struct perf_inject *inject;
>> +};
>> +
>> +static int feat_copy_cb(struct feat_copier *fc, int feat, struct feat_writer *fw)
>> +{
>> +	struct inject_fc *inj_fc = container_of(fc, struct inject_fc, fc);
>> +	struct perf_inject *inject = inj_fc->inject;
>> +	int ret;
>> +
>> +	if (!inject->secs[feat].offset ||
>> +	    !keep_feat(feat))
>> +		return 0;
>> +
>> +	ret = feat_copy(inject, feat, fw);
>> +	if (ret < 0)
>> +		return ret;
>> +
>> +	return 1; /* Feature section copied */
>> +}
>> +
>>  static int output_fd(struct perf_inject *inject)
>>  {
>>  	return inject->in_place_update ? -1 : perf_data__fd(&inject->output);
>> @@ -848,6 +965,11 @@ static int __cmd_inject(struct perf_inject *inject)
>>  		return ret;
>>  
>>  	if (!inject->is_pipe && !inject->in_place_update) {
>> +		struct inject_fc inj_fc = {
>> +			.fc.copy = feat_copy_cb,
>> +			.inject = inject,
>> +		};
>> +
>>  		if (inject->build_ids)
>>  			perf_header__set_feat(&session->header,
>>  					      HEADER_BUILD_ID);
>> @@ -872,7 +994,7 @@ static int __cmd_inject(struct perf_inject *inject)
>>  		}
>>  		session->header.data_offset = output_data_offset;
>>  		session->header.data_size = inject->bytes_written;
>> -		perf_session__write_header(session, session->evlist, fd, true);
>> +		perf_session__inject_header(session, session->evlist, fd, &inj_fc.fc);
>>  	}
>>  
>>  	return ret;
>> @@ -1037,6 +1159,11 @@ int cmd_inject(int argc, const char **argv)
>>  	if (zstd_init(&(inject.session->zstd_data), 0) < 0)
>>  		pr_warning("Decompression initialization failed.\n");
>>  
>> +	/* Save original section info before feature bits change */
>> +	ret = save_section_info(&inject);
>> +	if (ret)
>> +		goto out_delete;
>> +
>>  	if (!data.is_pipe && inject.output.is_pipe) {
>>  		ret = perf_header__write_pipe(perf_data__fd(&inject.output));
>>  		if (ret < 0) {
>> diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
>> index b0c57a130d1e..53332da100e8 100644
>> --- a/tools/perf/util/header.c
>> +++ b/tools/perf/util/header.c
>> @@ -3686,6 +3686,14 @@ int perf_session__write_header(struct perf_session *session,
>>  	return perf_session__do_write_header(session, evlist, fd, at_exit, NULL);
>>  }
>>  
>> +int perf_session__inject_header(struct perf_session *session,
>> +				struct evlist *evlist,
>> +				int fd,
>> +				struct feat_copier *fc)
>> +{
>> +	return perf_session__do_write_header(session, evlist, fd, true, fc);
>> +}
>> +
>>  static int perf_header__getbuffer64(struct perf_header *header,
>>  				    int fd, void *buf, size_t size)
>>  {
>> diff --git a/tools/perf/util/header.h b/tools/perf/util/header.h
>> index e76ab02d5541..08563c1f1bff 100644
>> --- a/tools/perf/util/header.h
>> +++ b/tools/perf/util/header.h
>> @@ -131,6 +131,11 @@ struct feat_copier {
>>  	int (*copy)(struct feat_copier *fc, int feat, struct feat_writer *fw);
>>  };
>>  
>> +int perf_session__inject_header(struct perf_session *session,
>> +				struct evlist *evlist,
>> +				int fd,
>> +				struct feat_copier *fc);
>> +
>>  void perf_header__set_feat(struct perf_header *header, int feat);
>>  void perf_header__clear_feat(struct perf_header *header, int feat);
>>  bool perf_header__has_feat(const struct perf_header *header, int feat);
>> -- 
>> 2.25.1
>>