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

[Arnaldo Carvalho de Melo <acme@kernel.org>]

Em Mon, Jan 08, 2018 at 12:55:34PM -0300, Arnaldo Carvalho de Melo escreveu:
> 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 :-)

And tested it, nice new feature! :-)

- Arnaldo
 
> - 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@git.kernel.org
> > Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> > ---
> >  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