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

From: Namhyung Kim
Date: Mon Jan 08 2018 - 20:56:16 EST


Hi Jiri,

On Sun, Jan 07, 2018 at 05:03:56PM +0100, Jiri Olsa wrote:
> 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.
>
> $ 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

Nice! :)


>
> 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);

I think it should be machine__find_thread() since creating a new
thread at this stage would lack thread->priv anyway.

Thanks,
Namhyung


> + 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);
> +}