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Re: [patchv2] Sort threads for thread apply all (bt)
- From: Doug Evans <dje at google dot com>
- To: Jan Kratochvil <jan dot kratochvil at redhat dot com>
- Cc: gdb-patches <gdb-patches at sourceware dot org>
- Date: Wed, 21 Jan 2015 16:26:46 -0800
- Subject: Re: [patchv2] Sort threads for thread apply all (bt)
- Authentication-results: sourceware.org; auth=none
- References: <20150115183316 dot GA16405 at host2 dot jankratochvil dot net> <CADPb22R_dY8nfU4bgpPS+4K5gG9cdMzCqW--H85hMwBDdh+MRg at mail dot gmail dot com> <20150116233802 dot GA8732 at host2 dot jankratochvil dot net>
Jan Kratochvil writes:
> On Thu, 15 Jan 2015 20:29:07 +0100, Doug Evans wrote:
> > On Thu, Jan 15, 2015 at 10:33 AM, Jan Kratochvil <jan.kratochvil@redhat.com> wrote:
> > > I find maybe as good enough and with no risk of UI change flamewar to just
> > > sort the threads by their number. Currently they are printed as they happen
> > > in the internal GDB list which has no advantage. Printing thread #1 as the
> > > first one with assumed 'thread apply all bt' (after the core file is loaded)
> > > should make the complaint resolved I guess.
> > >
> > > No regressions on {x86_64,x86_64-m32,i686}-fedora22pre-linux-gnu.
> >
> > No objection to sorting the list, but if thread #1 is the important one,
> > then a concern could be it'll have scrolled off the screen (such a
> > concern has been voiced in another thread in another context),
> > and if not lost (say it's in an emacs buffer) one would still have
> > to scroll back to see it.
> > So one *could* still want #1 to be last.
> > Do we want an option to choose the sort direction?
> > [I wouldn't make it a global parameter, just an option to
> > thread apply.]
>
> Done.
>
>
> Thanks,
> Jan
> gdb/ChangeLog
> 2015-01-16 Jan Kratochvil <jan.kratochvil@redhat.com>
>
> * thread.c (tp_array_compar_asc, tp_array_compar): New.
> (thread_apply_all_command): Parse CMD for tp_array_compar_asc. Sort
> tp_array using tp_array_compar.
> (_initialize_thread): Extend thread_apply_all_command help.
>
> gdb/doc/ChangeLog
> 2015-01-16 Jan Kratochvil <jan.kratochvil@redhat.com>
>
> * gdb.texinfo (Threads): Describe -asc for thread apply all.
Hi.
Just some nits, no need to resubmit for review.
>
> diff --git a/gdb/thread.c b/gdb/thread.c
> index ed20fbe..9685351 100644
> --- a/gdb/thread.c
> +++ b/gdb/thread.c
> @@ -1382,6 +1382,20 @@ make_cleanup_restore_current_thread (void)
> restore_current_thread_cleanup_dtor);
> }
>
> +static int tp_array_compar_asc;
This should probably have a comment.
> +
> +/* Sort an array for struct thread_info pointers by their ascending NUM. */
> +
> +static int
> +tp_array_compar (const void *ap_voidp, const void *bp_voidp)
> +{
> + const struct thread_info *const *ap = ap_voidp;
> + const struct thread_info *const *bp = bp_voidp;
> +
> + return ((((*ap)->num > (*bp)->num) - ((*ap)->num < (*bp)->num))
> + * (tp_array_compar_asc ? +1 : -1));
> +}
This triggers my "passing parameters as global variables" alarm,
and while one could instead have two different functions,
this is ok, at least for now.
> +
> /* Apply a GDB command to a list of threads. List syntax is a whitespace
> seperated list of numbers, or ranges, or the keyword `all'. Ranges consist
> of two numbers seperated by a hyphen. Examples:
> @@ -1398,6 +1412,13 @@ thread_apply_all_command (char *cmd, int from_tty)
> int tc;
> struct thread_array_cleanup ta_cleanup;
>
> + tp_array_compar_asc = 0;
> + if (cmd && (check_for_argument (&cmd, "-asc", strlen ("-asc"))))
cmd != NULL
> + {
> + cmd = skip_spaces (cmd);
> + tp_array_compar_asc = 1;
> + }
> +
> if (cmd == NULL || *cmd == '\000')
> error (_("Please specify a command following the thread ID list"));
>
> @@ -1431,6 +1452,8 @@ thread_apply_all_command (char *cmd, int from_tty)
> i++;
> }
>
> + qsort (tp_array, i, sizeof (*tp_array), tp_array_compar);
> +
> make_cleanup (set_thread_refcount, &ta_cleanup);
>
> for (k = 0; k != i; k++)
> @@ -1739,7 +1762,14 @@ The new thread ID must be currently known."),
> &thread_apply_list, "thread apply ", 1, &thread_cmd_list);
>
> add_cmd ("all", class_run, thread_apply_all_command,
> - _("Apply a command to all threads."), &thread_apply_list);
> + _("\
> +Apply a command to all threads.\n\
> +\n\
> +Usage: thread apply all [-asc] <command>\n\
> +-asc: Call <command> for all threads in ascending order.\n\
> + The default is descending order.\n\
No final trailing newline.
> +"),
> + &thread_apply_list);
>
> add_cmd ("name", class_run, thread_name_command,
> _("Set the current thread's name.\n\
> diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
> index f413e23..2207ce4 100644
> --- a/gdb/doc/gdb.texinfo
> +++ b/gdb/doc/gdb.texinfo
> @@ -2959,14 +2959,17 @@ information on convenience variables.
>
> @kindex thread apply
> @cindex apply command to several threads
> -@item thread apply [@var{threadno} | all] @var{command}
> +@item thread apply [@var{threadno} | all [-asc]] @var{command}
> The @code{thread apply} command allows you to apply the named
> @var{command} to one or more threads. Specify the numbers of the
> threads that you want affected with the command argument
> @var{threadno}. It can be a single thread number, one of the numbers
> shown in the first field of the @samp{info threads} display; or it
> -could be a range of thread numbers, as in @code{2-4}. To apply a
> -command to all threads, type @kbd{thread apply all @var{command}}.
> +could be a range of thread numbers, as in @code{2-4}. To apply
> +a command to all threads in descending order, type @kbd{thread apply all
> +@var{command}}. To apply a command to all threads in ascending order,
> +type @kbd{thread apply all -asc @var{command}}.
> +
>
> @kindex thread name
> @cindex name a thread