Date:	Fri, 10 Aug 2012 11:14:24 -0300
From:	Arnaldo Carvalho de Melo <acme@...radead.org>
To:	Dong Hao <haodong@...ux.vnet.ibm.com>
Cc:	avi@...hat.com, mtosatti@...hat.com, mingo@...e.hu,
	dsahern@...il.com, linux-kernel@...r.kernel.org,
	kvm@...r.kernel.org,
	Xiao Guangrong <xiaoguangrong@...ux.vnet.ibm.com>
Subject: Re: [PATCH v6 3/3] KVM: perf kvm events analysis tool

Em Fri, Aug 10, 2012 at 11:19:10AM +0800, Dong Hao escreveu:
> From: Xiao Guangrong <xiaoguangrong@...ux.vnet.ibm.com>
> 
> Add 'perf kvm stat' support to analyze kvm vmexit/mmio/ioport smartly.

Some comments below about recent changes in my perf/core branch.
> +static void process_raw_event(struct thread *thread, void *data, u64 timestamp)
> +{
> +	struct event_format *event;
> +	int type;
> +
> +	type = trace_parse_common_type(kvm_session->pevent, data);

type can be found in evsel->attr.config

> +	event = pevent_find_event(kvm_session->pevent, type);

event in evsel->tp_format, i.e. no need to relookup via
pevent_find_event.

> +	return handle_kvm_event(thread, event, data, timestamp);
> +}
> +
> +static int process_sample_event(struct perf_tool *tool __used,
> +				union perf_event *event,
> +				struct perf_sample *sample,
> +				struct perf_evsel *evsel __used,
> +				struct machine *machine)
> +{
> +	struct thread *thread = machine__findnew_thread(machine, sample->tid);
> +
> +	if (thread == NULL) {
> +		pr_debug("problem processing %d event, skipping it.\n",
> +			event->header.type);
> +		return -1;
> +	}
> +
> +	process_raw_event(thread, sample->raw_data, sample->time);
> +
> +	return 0;
> +}
> +
> +static struct perf_tool eops = {
> +	.sample			= process_sample_event,
> +	.comm			= perf_event__process_comm,
> +	.ordered_samples	= true,
> +};
> +
> +static int get_cpu_isa(struct perf_session *session)
> +{
> +	char *cpuid;
> +	int isa;
> +
> +	cpuid = perf_header__read_feature(session, HEADER_CPUID);
> +
> +	if (!cpuid)
> +		die("read HEADER_CPUID failed.\n");

Please don't use die, use pr_err and return -1, so that whatever cleanup
code the main perf tool needs to do gets done.

> +	if (strstr(cpuid, "Intel"))
> +		isa = 1;
> +	else if (strstr(cpuid, "AMD"))
> +		isa = 0;
> +	else
> +		die("CPU %s is not supported.\n", cpuid);

Ditto

> +	free(cpuid);
> +	return isa;
> +}
> +
> +static const char *file_name;
> +
> +static int read_events(void)
> +{
> +	kvm_session = perf_session__new(file_name, O_RDONLY, 0, false, &eops);
> +	if (!kvm_session)
> +		die("Initializing perf session failed\n");

Ditto

> +	if (!perf_session__has_traces(kvm_session, "kvm record"))
> +		return -1;
> +
> +	/*
> +	 * Do not use 'isa' recorded in kvm_exit tracepoint since it is not
> +	 * traced in the old kernel.
> +	 */
> +	cpu_isa = get_cpu_isa(kvm_session);
> +
> +	return perf_session__process_events(kvm_session, &eops);
> +}
> +
> +static void verify_vcpu(int vcpu)
> +{
> +	if (vcpu != -1 && vcpu < 0)
> +		die("Invalid vcpu:%d.\n", vcpu);

Ditto

> +}
> +
> +static int kvm_events_report_vcpu(int vcpu)
> +{
> +	init_kvm_event_record();
> +	verify_vcpu(vcpu);
> +	select_key();
> +	register_kvm_events_ops();
> +	setup_pager();
> +
> +	read_events();
> +
> +	sort_result(vcpu);
> +	print_result(vcpu);
> +	return 0;
> +}
> +
> +static const char * const record_args[] = {
> +	"record",
> +	"-R",
> +	"-f",
> +	"-m", "1024",
> +	"-c", "1",
> +	"-e", "kvm:kvm_entry",
> +	"-e", "kvm:kvm_exit",
> +	"-e", "kvm:kvm_mmio",
> +	"-e", "kvm:kvm_pio",
> +};
> +
> +static const char * const new_event[] = {
> +	"kvm_mmio_begin",
> +	"kvm_mmio_done"
> +};
> +
> +static bool kvm_events_exist(const char *event)
> +{
> +	char evt_path[MAXPATHLEN];
> +	int fd;
> +
> +	snprintf(evt_path, MAXPATHLEN, "%s/kvm/%s/id", tracing_events_path,
> +		 event);
> +
> +	fd = open(evt_path, O_RDONLY);
> +
> +	if (fd < 0)
> +		return false;
> +
> +	close(fd);
> +
> +	return true;
> +}
> +
> +static bool kvm_record_specified_guest(int argc, const char **argv)
> +{
> +	int i;
> +
> +	for (i = 0; i < argc; i++)
> +		if (!strcmp(argv[i], "-p") || !strcmp(argv[i], "--pid"))
> +			return true;
> +
> +	return false;
> +}
> +
> +static int kvm_events_record(int argc, const char **argv)
> +{
> +	unsigned int rec_argc, i, j;
> +	const char **rec_argv;
> +
> +	rec_argc = ARRAY_SIZE(record_args) + argc + 2;
> +	rec_argc += ARRAY_SIZE(new_event) * 2;
> +	rec_argv = calloc(rec_argc + 1, sizeof(char *));
> +
> +	if (rec_argv == NULL)
> +		return -ENOMEM;

Just like you do here :-)

> +	for (i = 0; i < ARRAY_SIZE(record_args); i++)
> +		rec_argv[i] = strdup(record_args[i]);
> +
> +	/*
> +	 * Append "-a" only if "-p"/"--pid" is not specified since they
> +	 * are mutually exclusive.
> +	 */
> +	if (!kvm_record_specified_guest(argc, argv))
> +		rec_argv[i++] = strdup("-a");
> +
> +	rec_argv[i++] = strdup("-o");
> +	rec_argv[i++] = strdup(file_name);
> +
> +	for (j = 0; j < ARRAY_SIZE(new_event); j++)
> +		if (kvm_events_exist(new_event[j])) {
> +			char event[256];
> +
> +			sprintf(event, "kvm:%s", new_event[j]);
> +
> +			rec_argv[i++] = strdup("-e");
> +			rec_argv[i++] = strdup(event);

these can fail

> +		}
> +
> +	for (j = 1; j < (unsigned int)argc; j++, i++)
> +		rec_argv[i] = argv[j];
> +
> +	return cmd_record(i, rec_argv, NULL);
> +}
> +
> +static const char * const kvm_events_report_usage[] = {
> +	"perf kvm stat report [<options>]",
> +	NULL
> +};
> +
> +static const struct option kvm_events_report_options[] = {
> +	OPT_STRING(0, "event", &report_event, "report event",
> +		    "event for reporting: vmexit, mmio, ioport"),
> +	OPT_INTEGER(0, "vcpu", &trace_vcpu,
> +		    "vcpu id to report"),
> +	OPT_STRING('k', "key", &sort_key, "sort-key",
> +		    "key for sorting: sample(sort by samples number)"
> +		    " time (sort by avg time)"),
> +	OPT_END()
> +};
> +
> +static int kvm_events_report(int argc, const char **argv)
> +{
> +	symbol__init();
> +
> +	if (argc) {
> +		argc = parse_options(argc, argv,
> +				     kvm_events_report_options,
> +				     kvm_events_report_usage, 0);
> +		if (argc)
> +			usage_with_options(kvm_events_report_usage,
> +					   kvm_events_report_options);
> +	}
> +
> +	return kvm_events_report_vcpu(trace_vcpu);
> +}
> +
> +static int kvm_cmd_stat(int argc, const char **argv)
> +{
> +	if (argc > 1) {
> +		if (!strncmp(argv[1], "rec", 3))
> +			return kvm_events_record(argc - 1, argv + 1);
> +
> +		if (!strncmp(argv[1], "rep", 3))
> +			return kvm_events_report(argc - 1 , argv + 1);
> +	}
> +
> +	return cmd_stat(argc, argv, NULL);
> +}
> +
>  static char			name_buffer[256];
>  
>  static const char * const kvm_usage[] = {
> -	"perf kvm [<options>] {top|record|report|diff|buildid-list}",
> +	"perf kvm [<options>] {top|record|report|diff|buildid-list|stat}",
>  	NULL
>  };
>  
> @@ -135,6 +985,8 @@ int cmd_kvm(int argc, const char **argv, const char *prefix __used)
>  		return cmd_top(argc, argv, NULL);
>  	else if (!strncmp(argv[0], "buildid-list", 12))
>  		return __cmd_buildid_list(argc, argv);
> +	else if (!strncmp(argv[0], "stat", 4))
> +		return kvm_cmd_stat(argc, argv);
>  	else
>  		usage_with_options(kvm_usage, kvm_options);
>  
> diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
> index 3a6d204..b4bef64 100644
> --- a/tools/perf/util/header.c
> +++ b/tools/perf/util/header.c
> @@ -1495,9 +1495,15 @@ static int process_build_id(struct perf_file_section *section,
>  	return 0;
>  }
>  
> +static char *read_cpuid(struct perf_header *ph, int fd)
> +{
> +	return do_read_string(fd, ph);
> +}
> +
>  struct feature_ops {
>  	int (*write)(int fd, struct perf_header *h, struct perf_evlist *evlist);
>  	void (*print)(struct perf_header *h, int fd, FILE *fp);
> +	char *(*read)(struct perf_header *h, int fd);
>  	int (*process)(struct perf_file_section *section,
>  		       struct perf_header *h, int feat, int fd, void *data);
>  	const char *name;
> @@ -1512,6 +1518,9 @@ struct feature_ops {
>  #define FEAT_OPF(n, func) \
>  	[n] = { .name = #n, .write = write_##func, .print = print_##func, \
>  		.full_only = true }
> +#define FEAT_OPA_R(n, func) \
> +	[n] = { .name = #n, .write = write_##func, .print = print_##func, \
> +		.read  = read_##func }
>  
>  /* feature_ops not implemented: */
>  #define print_tracing_data	NULL
> @@ -1526,7 +1535,7 @@ static const struct feature_ops feat_ops[HEADER_LAST_FEATURE] = {
>  	FEAT_OPA(HEADER_ARCH,		arch),
>  	FEAT_OPA(HEADER_NRCPUS,		nrcpus),
>  	FEAT_OPA(HEADER_CPUDESC,	cpudesc),
> -	FEAT_OPA(HEADER_CPUID,		cpuid),
> +	FEAT_OPA_R(HEADER_CPUID,	cpuid),
>  	FEAT_OPA(HEADER_TOTAL_MEM,	total_mem),
>  	FEAT_OPA(HEADER_EVENT_DESC,	event_desc),
>  	FEAT_OPA(HEADER_CMDLINE,	cmdline),
> @@ -1580,6 +1589,50 @@ int perf_header__fprintf_info(struct perf_session *session, FILE *fp, bool full)
>  	return 0;
>  }
>  
> +struct header_read_data {
> +	int feat;
> +	char *result;
> +};
> +
> +static int perf_file_section__read_feature(struct perf_file_section *section,
> +					   struct perf_header *ph,
> +					   int feat, int fd, void *data)
> +{
> +	struct header_read_data *hd = data;
> +
> +	if (feat != hd->feat)
> +		return 0;
> +
> +	if (lseek(fd, section->offset, SEEK_SET) == (off_t)-1) {
> +		pr_debug("Failed to lseek to %" PRIu64 " offset for feature "
> +				"%d, continuing...\n", section->offset, feat);
> +		return 0;
> +	}
> +
> +	if (feat >= HEADER_LAST_FEATURE) {
> +		pr_warning("unknown feature %d\n", feat);
> +		return 0;
> +	}
> +
> +	hd->result = feat_ops[feat].read(ph, fd);
> +	return 0;
> +}
> +
> +char *perf_header__read_feature(struct perf_session *session, int feat)
> +{
> +	struct perf_header *header = &session->header;
> +	struct header_read_data hd;
> +	int fd = session->fd;
> +
> +	hd.feat = feat;
> +	hd.result = NULL;
> +
> +

Extra new line

> +	perf_header__process_sections(header, fd, &hd,
> +				  perf_file_section__read_feature);
> +	return hd.result;
> +}
> +
>  static int do_write_feat(int fd, struct perf_header *h, int type,
>  			 struct perf_file_section **p,
>  			 struct perf_evlist *evlist)
> diff --git a/tools/perf/util/header.h b/tools/perf/util/header.h
> index 2d42b3e..a8830fa 100644
> --- a/tools/perf/util/header.h
> +++ b/tools/perf/util/header.h
> @@ -93,6 +93,7 @@ int perf_header__process_sections(struct perf_header *header, int fd,
>  				  int feat, int fd, void *data));
>  
>  int perf_header__fprintf_info(struct perf_session *s, FILE *fp, bool full);
> +char *perf_header__read_feature(struct perf_session *session, int feat);
>  
>  int build_id_cache__add_s(const char *sbuild_id, const char *debugdir,
>  			  const char *name, bool is_kallsyms);
> diff --git a/tools/perf/util/thread.h b/tools/perf/util/thread.h
> index 70c2c13..c48ebf3 100644
> --- a/tools/perf/util/thread.h
> +++ b/tools/perf/util/thread.h
> @@ -16,6 +16,8 @@ struct thread {
>  	bool			comm_set;
>  	char			*comm;
>  	int			comm_len;
> +
> +	void			*private;

Please use the shorter 'priv', like {evsel,map}->priv

>  };
>  
>  struct machine;
> -- 
> 1.7.2.5
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