Re: [PATCH 12/12] perf report: Add --task option to display monitored tasks

[Arnaldo Carvalho de Melo]

Em Sun, Jan 07, 2018 at 05:03:56PM +0100, Jiri Olsa escreveu:
> Adding --task option to display monitored tasks stored
> in perf.data. Displaying pid/tid/ppid plus the command
> string aligned to distinguish parent and child tasks.

I'm making this --tasks, plural, but then you can also use --task :-)

- Arnaldo
 
>   $ perf record -a
>   ...
>   $ perf report --task
>   #     pid     tid    ppid  comm
>           0       0      -1 |swapper
>           2       2       0 | kthreadd
>       14080   14080       2 |  kworker/u17:1
>           4       4       2 |  kworker/0:0H
>           6       6       2 |  mm_percpu_wq
>   ...
>           1       1       0 | systemd
>       23242   23242       1 |  firefox
>       23242   23298   23242 |   Cache2 I/O
>       23242   23304   23242 |   GMPThread
>   ...
>        1195    1195       1 |  login
>        1611    1611    1195 |   bash
>        1639    1639    1611 |    startx
>        1663    1663    1639 |     xinit
>        1673    1673    1663 |      xmonad-x86_64-l
>       23939   23939    1673 |       xterm
>       23941   23941   23939 |        bash
>       23963   23963   23941 |         mutt
>       24954   24954   23963 |          offlineimap
> 
> Link: http://lkml.kernel.org/n/tip-ehvadnmg8b3kdhvgsbuesbr7@xxxxxxxxxxxxxx
> Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
> ---
>  tools/perf/Documentation/perf-report.txt |   4 +
>  tools/perf/builtin-report.c              | 136 ++++++++++++++++++++++++++++++-
>  2 files changed, 138 insertions(+), 2 deletions(-)
> 
> diff --git a/tools/perf/Documentation/perf-report.txt b/tools/perf/Documentation/perf-report.txt
> index b0d70bf4ddfe..dcf0d154918f 100644
> --- a/tools/perf/Documentation/perf-report.txt
> +++ b/tools/perf/Documentation/perf-report.txt
> @@ -441,6 +441,10 @@ include::itrace.txt[]
>  	Display overall events statistics without any further processing.
>  	(like the one at the end of the perf report -D command)
>  
> +--task::
> +	Display monitored tasks stored in perf data. Displaying pid/tid/ppid
> +	plus the command string aligned to distinguish parent and child tasks.
> +
>  include::callchain-overhead-calculation.txt[]
>  
>  SEE ALSO
> diff --git a/tools/perf/builtin-report.c b/tools/perf/builtin-report.c
> index 11d303494b0c..f2ca2cbe63c1 100644
> --- a/tools/perf/builtin-report.c
> +++ b/tools/perf/builtin-report.c
> @@ -15,6 +15,7 @@
>  #include "util/color.h"
>  #include <linux/list.h>
>  #include <linux/rbtree.h>
> +#include <linux/err.h>
>  #include "util/symbol.h"
>  #include "util/callchain.h"
>  #include "util/values.h"
> @@ -61,6 +62,7 @@ struct report {
>  	bool			inverted_callchain;
>  	bool			mem_mode;
>  	bool			stat_mode;
> +	bool			task_mode;
>  	bool			header;
>  	bool			header_only;
>  	bool			nonany_branch_mode;
> @@ -598,6 +600,124 @@ static int stat_print(struct report *rep)
>  	return 0;
>  }
>  
> +static void task_setup(struct report *rep)
> +{
> +	memset(&rep->tool, 0, sizeof(rep->tool));
> +	rep->tool.comm = perf_event__process_comm;
> +	rep->tool.exit = perf_event__process_exit;
> +	rep->tool.fork = perf_event__process_fork;
> +	rep->tool.no_warn = true;
> +}
> +
> +struct task {
> +	struct thread		*thread;
> +	struct list_head	 list;
> +	struct list_head	 children;
> +};
> +
> +static struct task *task_list(struct task *task, struct machine *machine)
> +{
> +	struct thread *parent_thread, *thread = task->thread;
> +	struct task   *parent_task;
> +
> +	/* Already listed. */
> +	if (!list_empty(&task->list))
> +		return NULL;
> +
> +	/* Last one in the chain. */
> +	if (thread->ppid == -1)
> +		return task;
> +
> +	parent_thread = machine__findnew_thread(machine, -1, thread->ppid);
> +	if (!parent_thread)
> +		return ERR_PTR(-ENOMEM);
> +
> +	parent_task = thread__priv(parent_thread);
> +	list_add_tail(&task->list, &parent_task->children);
> +	return task_list(parent_task, machine);
> +}
> +
> +static void task__print_level(struct task *task, FILE *fp, int level)
> +{
> +	struct thread *thread = task->thread;
> +	struct task *child;
> +
> +	fprintf(fp, "  %8d %8d %8d |%*s%s\n",
> +		thread->pid_, thread->tid, thread->ppid,
> +		level, "", thread__comm_str(thread));
> +
> +	if (!list_empty(&task->children)) {
> +		list_for_each_entry(child, &task->children, list)
> +			task__print_level(child, fp, level + 1);
> +	}
> +}
> +
> +static int task_print(struct report *rep, FILE *fp)
> +{
> +	struct perf_session *session = rep->session;
> +	struct machine      *machine = &session->machines.host;
> +	struct task *tasks, *task;
> +	unsigned int nr = 0, itask = 0, i;
> +	struct rb_node *nd;
> +	LIST_HEAD(list);
> +
> +	/*
> +	 * No locking needed while accessing machine->threads,
> +	 * because --task is single threaded command.
> +	 */
> +
> +	/* Count all the threads. */
> +	for (i = 0; i < THREADS__TABLE_SIZE; i++)
> +		nr += machine->threads[i].nr;
> +
> +	tasks = malloc(sizeof(*tasks) * nr);
> +	if (!tasks)
> +		return -ENOMEM;
> +
> +	for (i = 0; i < THREADS__TABLE_SIZE; i++) {
> +		struct threads *threads = &machine->threads[i];
> +
> +		for (nd = rb_first(&threads->entries); nd; nd = rb_next(nd)) {
> +			task = tasks + itask++;
> +
> +			task->thread = rb_entry(nd, struct thread, rb_node);
> +			INIT_LIST_HEAD(&task->children);
> +			INIT_LIST_HEAD(&task->list);
> +			thread__set_priv(task->thread, task);
> +		}
> +	}
> +
> +	/*
> +	 * Iterate every task down to the unprocessed parent
> +	 * and link all in task children list. Task with no
> +	 * parent is added into 'list'.
> +	 */
> +	for (itask = 0; itask < nr; itask++) {
> +		task = tasks + itask;
> +
> +		if (!list_empty(&task->list))
> +			continue;
> +
> +		task = task_list(task, machine);
> +		if (IS_ERR(task)) {
> +			pr_err("Error: failed to process tasks\n");
> +			free(tasks);
> +			return -ENOMEM;
> +		}
> +
> +		if (task)
> +			list_add_tail(&task->list, &list);
> +	}
> +
> +	fprintf(fp, "# %8s %8s %8s  %s\n", "pid", "tid", "ppid", "comm");
> +
> +	list_for_each_entry(task, &list, list)
> +		task__print_level(task, fp, 0);
> +
> +	free(tasks);
> +	return 0;
> +}
> +
>  static int __cmd_report(struct report *rep)
>  {
>  	int ret;
> @@ -632,6 +752,9 @@ static int __cmd_report(struct report *rep)
>  	if (rep->stat_mode)
>  		stat_setup(rep);
>  
> +	if (rep->task_mode)
> +		task_setup(rep);
> +
>  	ret = perf_session__process_events(session);
>  	if (ret) {
>  		ui__error("failed to process sample\n");
> @@ -641,6 +764,9 @@ static int __cmd_report(struct report *rep)
>  	if (rep->stat_mode)
>  		return stat_print(rep);
>  
> +	if (rep->task_mode)
> +		return task_print(rep, stdout);
> +
>  	report__warn_kptr_restrict(rep);
>  
>  	evlist__for_each_entry(session->evlist, pos)
> @@ -798,6 +924,7 @@ int cmd_report(int argc, const char **argv)
>  	OPT_BOOLEAN('D', "dump-raw-trace", &dump_trace,
>  		    "dump raw trace in ASCII"),
>  	OPT_BOOLEAN(0, "stat", &report.stat_mode, "Display event stats"),
> +	OPT_BOOLEAN(0, "task", &report.task_mode, "Display recorded tasks"),
>  	OPT_STRING('k', "vmlinux", &symbol_conf.vmlinux_name,
>  		   "file", "vmlinux pathname"),
>  	OPT_STRING(0, "kallsyms", &symbol_conf.kallsyms_name,
> @@ -1059,8 +1186,12 @@ int cmd_report(int argc, const char **argv)
>  		report.tool.show_feat_hdr = SHOW_FEAT_HEADER;
>  	if (report.show_full_info)
>  		report.tool.show_feat_hdr = SHOW_FEAT_HEADER_FULL_INFO;
> -	if (report.stat_mode)
> +	if (report.stat_mode || report.task_mode)
>  		use_browser = 0;
> +	if (report.stat_mode && report.task_mode) {
> +		pr_err("Error: --task and --stat options cannot be used together\n");
> +		goto error;
> +	}
>  
>  	if (strcmp(input_name, "-") != 0)
>  		setup_browser(true);
> @@ -1083,7 +1214,8 @@ int cmd_report(int argc, const char **argv)
>  			ret = 0;
>  			goto error;
>  		}
> -	} else if (use_browser == 0 && !quiet && !report.stat_mode) {
> +	} else if (use_browser == 0 && !quiet &&
> +		   !report.stat_mode && !report.task_mode) {
>  		fputs("# To display the perf.data header info, please use --header/--header-only options.\n#\n",
>  		      stdout);
>  	}
> -- 
> 2.13.6