[v2,1/2] perf tui: don't ignore job control

  In its infinite wisdom, by default, SLang sets susp undef,
and this can only be un-done by calling SLtty_set_suspend_state(true).
After every SLang_init_tty().

Additionally, no provisions are made for maintaining the teletype
attributes across suspend/continue (outside of curses emulation mode(?!),
which provides full support, naturally), so we need to save and restore
the flags ourselves, as well as reset the text colours when going under.
We need to also re-draw the screen, and raising SIGWINCH, shockingly,
Just Works.

The correct solution would be to Not Use SLang, but as a stop-gap,
this makes TUI perf report usable.

Signed-off-by: Ahelenia Ziemiańska <nabijaczleweli@nabijaczleweli.xyz>
---
Yeah, somehow I didn't hit that in my tests, but it was relatively easy
to trigger when I tried. A full partial write retry loop is an overkill
here, I think, and few other places in perf actually try to resubmit
partial writes, so.

 tools/perf/ui/browsers/annotate.c |  1 +
 tools/perf/ui/browsers/hists.c    |  2 ++
 tools/perf/ui/browsers/scripts.c  |  1 +
 tools/perf/ui/tui/setup.c         | 22 ++++++++++++++++++++++
 4 files changed, 26 insertions(+)
  

On Tue, Dec 27, 2022 at 12:57 PM Ahelenia Ziemiańska
<nabijaczleweli@nabijaczleweli.xyz> wrote:
>
> In its infinite wisdom, by default, SLang sets susp undef,
> and this can only be un-done by calling SLtty_set_suspend_state(true).
> After every SLang_init_tty().
>
> Additionally, no provisions are made for maintaining the teletype
> attributes across suspend/continue (outside of curses emulation mode(?!),
> which provides full support, naturally), so we need to save and restore
> the flags ourselves, as well as reset the text colours when going under.
> We need to also re-draw the screen, and raising SIGWINCH, shockingly,
> Just Works.
>
> The correct solution would be to Not Use SLang, but as a stop-gap,
> this makes TUI perf report usable.
>
> Signed-off-by: Ahelenia Ziemiańska <nabijaczleweli@nabijaczleweli.xyz>

Tested-by: Namhyung Kim <namhyung@kernel.org>

Thanks,
Namhyung


> ---
> Yeah, somehow I didn't hit that in my tests, but it was relatively easy
> to trigger when I tried. A full partial write retry loop is an overkill
> here, I think, and few other places in perf actually try to resubmit
> partial writes, so.
>
>  tools/perf/ui/browsers/annotate.c |  1 +
>  tools/perf/ui/browsers/hists.c    |  2 ++
>  tools/perf/ui/browsers/scripts.c  |  1 +
>  tools/perf/ui/tui/setup.c         | 22 ++++++++++++++++++++++
>  4 files changed, 26 insertions(+)
>
> diff --git a/tools/perf/ui/browsers/annotate.c b/tools/perf/ui/browsers/annotate.c
> index c03fa76c02ff..6a4ffbf66c7f 100644
> --- a/tools/perf/ui/browsers/annotate.c
> +++ b/tools/perf/ui/browsers/annotate.c
> @@ -942,6 +942,7 @@ int hist_entry__tui_annotate(struct hist_entry *he, struct evsel *evsel,
>         /* reset abort key so that it can get Ctrl-C as a key */
>         SLang_reset_tty();
>         SLang_init_tty(0, 0, 0);
> +       SLtty_set_suspend_state(true);
>
>         return map_symbol__tui_annotate(&he->ms, evsel, hbt, opts);
>  }
> diff --git a/tools/perf/ui/browsers/hists.c b/tools/perf/ui/browsers/hists.c
> index b72ee6822222..2479e6d42e7c 100644
> --- a/tools/perf/ui/browsers/hists.c
> +++ b/tools/perf/ui/browsers/hists.c
> @@ -3010,6 +3010,7 @@ static int evsel__hists_browse(struct evsel *evsel, int nr_events, const char *h
>         /* reset abort key so that it can get Ctrl-C as a key */
>         SLang_reset_tty();
>         SLang_init_tty(0, 0, 0);
> +       SLtty_set_suspend_state(true);
>
>         if (min_pcnt)
>                 browser->min_pcnt = min_pcnt;
> @@ -3682,6 +3683,7 @@ int block_hists_tui_browse(struct block_hist *bh, struct evsel *evsel,
>         /* reset abort key so that it can get Ctrl-C as a key */
>         SLang_reset_tty();
>         SLang_init_tty(0, 0, 0);
> +       SLtty_set_suspend_state(true);
>
>         memset(&action, 0, sizeof(action));
>
> diff --git a/tools/perf/ui/browsers/scripts.c b/tools/perf/ui/browsers/scripts.c
> index 47d2c7a8cbe1..50d45054ed6c 100644
> --- a/tools/perf/ui/browsers/scripts.c
> +++ b/tools/perf/ui/browsers/scripts.c
> @@ -166,6 +166,7 @@ void run_script(char *cmd)
>         printf("\033[c\033[H\033[J");
>         fflush(stdout);
>         SLang_init_tty(0, 0, 0);
> +       SLtty_set_suspend_state(true);
>         SLsmg_refresh();
>  }
>
> diff --git a/tools/perf/ui/tui/setup.c b/tools/perf/ui/tui/setup.c
> index a3b8c397c24d..09524ba04975 100644
> --- a/tools/perf/ui/tui/setup.c
> +++ b/tools/perf/ui/tui/setup.c
> @@ -2,12 +2,14 @@
>  #include <signal.h>
>  #include <stdbool.h>
>  #include <stdlib.h>
> +#include <termios.h>
>  #include <unistd.h>
>  #include <linux/kernel.h>
>  #ifdef HAVE_BACKTRACE_SUPPORT
>  #include <execinfo.h>
>  #endif
>
> +#include "../../util/color.h"
>  #include "../../util/debug.h"
>  #include "../../perf.h"
>  #include "../browser.h"
> @@ -122,6 +124,23 @@ static void ui__signal(int sig)
>         exit(0);
>  }
>
> +static void ui__sigcont(int sig)
> +{
> +       static struct termios tty;
> +
> +       if (sig == SIGTSTP) {
> +               while (tcgetattr(SLang_TT_Read_FD, &tty) == -1 && errno == EINTR)
> +                       ;
> +               while (write(SLang_TT_Read_FD, PERF_COLOR_RESET, sizeof(PERF_COLOR_RESET) - 1) == -1 && errno == EINTR)
> +                       ;
> +               raise(SIGSTOP);
> +       } else {
> +               while (tcsetattr(SLang_TT_Read_FD, TCSADRAIN, &tty) == -1 && errno == EINTR)
> +                       ;
> +               raise(SIGWINCH);
> +       }
> +}
> +
>  int ui__init(void)
>  {
>         int err;
> @@ -136,6 +155,7 @@ int ui__init(void)
>         err = SLang_init_tty(-1, 0, 0);
>         if (err < 0)
>                 goto out;
> +       SLtty_set_suspend_state(true);
>
>         err = SLkp_init();
>         if (err < 0) {
> @@ -150,6 +170,8 @@ int ui__init(void)
>         signal(SIGINT, ui__signal);
>         signal(SIGQUIT, ui__signal);
>         signal(SIGTERM, ui__signal);
> +       signal(SIGTSTP, ui__sigcont);
> +       signal(SIGCONT, ui__sigcont);
>
>         perf_error__register(&perf_tui_eops);
>
> --
> 2.30.2
>
  

Em Tue, Dec 27, 2022 at 09:57:40PM +0100, Ahelenia Ziemiańska escreveu:
> In its infinite wisdom, by default, SLang sets susp undef,
> and this can only be un-done by calling SLtty_set_suspend_state(true).
> After every SLang_init_tty().
> 
> Additionally, no provisions are made for maintaining the teletype
> attributes across suspend/continue (outside of curses emulation mode(?!),
> which provides full support, naturally), so we need to save and restore
> the flags ourselves, as well as reset the text colours when going under.
> We need to also re-draw the screen, and raising SIGWINCH, shockingly,
> Just Works.
> 
> The correct solution would be to Not Use SLang, but as a stop-gap,
> this makes TUI perf report usable.
> 
> Signed-off-by: Ahelenia Ziemiańska <nabijaczleweli@nabijaczleweli.xyz>
> ---
> Yeah, somehow I didn't hit that in my tests, but it was relatively easy
> to trigger when I tried. A full partial write retry loop is an overkill
> here, I think, and few other places in perf actually try to resubmit
> partial writes, so.

We've been with this problem since forever, so I'll apply it to
perf/core, i.e. for the next merge window, ok?

- Arnaldo
 
>  tools/perf/ui/browsers/annotate.c |  1 +
>  tools/perf/ui/browsers/hists.c    |  2 ++
>  tools/perf/ui/browsers/scripts.c  |  1 +
>  tools/perf/ui/tui/setup.c         | 22 ++++++++++++++++++++++
>  4 files changed, 26 insertions(+)
> 
> diff --git a/tools/perf/ui/browsers/annotate.c b/tools/perf/ui/browsers/annotate.c
> index c03fa76c02ff..6a4ffbf66c7f 100644
> --- a/tools/perf/ui/browsers/annotate.c
> +++ b/tools/perf/ui/browsers/annotate.c
> @@ -942,6 +942,7 @@ int hist_entry__tui_annotate(struct hist_entry *he, struct evsel *evsel,
>  	/* reset abort key so that it can get Ctrl-C as a key */
>  	SLang_reset_tty();
>  	SLang_init_tty(0, 0, 0);
> +	SLtty_set_suspend_state(true);
>  
>  	return map_symbol__tui_annotate(&he->ms, evsel, hbt, opts);
>  }
> diff --git a/tools/perf/ui/browsers/hists.c b/tools/perf/ui/browsers/hists.c
> index b72ee6822222..2479e6d42e7c 100644
> --- a/tools/perf/ui/browsers/hists.c
> +++ b/tools/perf/ui/browsers/hists.c
> @@ -3010,6 +3010,7 @@ static int evsel__hists_browse(struct evsel *evsel, int nr_events, const char *h
>  	/* reset abort key so that it can get Ctrl-C as a key */
>  	SLang_reset_tty();
>  	SLang_init_tty(0, 0, 0);
> +	SLtty_set_suspend_state(true);
>  
>  	if (min_pcnt)
>  		browser->min_pcnt = min_pcnt;
> @@ -3682,6 +3683,7 @@ int block_hists_tui_browse(struct block_hist *bh, struct evsel *evsel,
>  	/* reset abort key so that it can get Ctrl-C as a key */
>  	SLang_reset_tty();
>  	SLang_init_tty(0, 0, 0);
> +	SLtty_set_suspend_state(true);
>  
>  	memset(&action, 0, sizeof(action));
>  
> diff --git a/tools/perf/ui/browsers/scripts.c b/tools/perf/ui/browsers/scripts.c
> index 47d2c7a8cbe1..50d45054ed6c 100644
> --- a/tools/perf/ui/browsers/scripts.c
> +++ b/tools/perf/ui/browsers/scripts.c
> @@ -166,6 +166,7 @@ void run_script(char *cmd)
>  	printf("\033[c\033[H\033[J");
>  	fflush(stdout);
>  	SLang_init_tty(0, 0, 0);
> +	SLtty_set_suspend_state(true);
>  	SLsmg_refresh();
>  }
>  
> diff --git a/tools/perf/ui/tui/setup.c b/tools/perf/ui/tui/setup.c
> index a3b8c397c24d..09524ba04975 100644
> --- a/tools/perf/ui/tui/setup.c
> +++ b/tools/perf/ui/tui/setup.c
> @@ -2,12 +2,14 @@
>  #include <signal.h>
>  #include <stdbool.h>
>  #include <stdlib.h>
> +#include <termios.h>
>  #include <unistd.h>
>  #include <linux/kernel.h>
>  #ifdef HAVE_BACKTRACE_SUPPORT
>  #include <execinfo.h>
>  #endif
>  
> +#include "../../util/color.h"
>  #include "../../util/debug.h"
>  #include "../../perf.h"
>  #include "../browser.h"
> @@ -122,6 +124,23 @@ static void ui__signal(int sig)
>  	exit(0);
>  }
>  
> +static void ui__sigcont(int sig)
> +{
> +	static struct termios tty;
> +
> +	if (sig == SIGTSTP) {
> +		while (tcgetattr(SLang_TT_Read_FD, &tty) == -1 && errno == EINTR)
> +			;
> +		while (write(SLang_TT_Read_FD, PERF_COLOR_RESET, sizeof(PERF_COLOR_RESET) - 1) == -1 && errno == EINTR)
> +			;
> +		raise(SIGSTOP);
> +	} else {
> +		while (tcsetattr(SLang_TT_Read_FD, TCSADRAIN, &tty) == -1 && errno == EINTR)
> +			;
> +		raise(SIGWINCH);
> +	}
> +}
> +
>  int ui__init(void)
>  {
>  	int err;
> @@ -136,6 +155,7 @@ int ui__init(void)
>  	err = SLang_init_tty(-1, 0, 0);
>  	if (err < 0)
>  		goto out;
> +	SLtty_set_suspend_state(true);
>  
>  	err = SLkp_init();
>  	if (err < 0) {
> @@ -150,6 +170,8 @@ int ui__init(void)
>  	signal(SIGINT, ui__signal);
>  	signal(SIGQUIT, ui__signal);
>  	signal(SIGTERM, ui__signal);
> +	signal(SIGTSTP, ui__sigcont);
> +	signal(SIGCONT, ui__sigcont);
>  
>  	perf_error__register(&perf_tui_eops);
>  
> -- 
> 2.30.2
>
  

Em Tue, Dec 27, 2022 at 09:57:40PM +0100, Ahelenia Ziemiańska escreveu:
> In its infinite wisdom, by default, SLang sets susp undef,
> and this can only be un-done by calling SLtty_set_suspend_state(true).
> After every SLang_init_tty().
> 
> Additionally, no provisions are made for maintaining the teletype
> attributes across suspend/continue (outside of curses emulation mode(?!),
> which provides full support, naturally), so we need to save and restore
> the flags ourselves, as well as reset the text colours when going under.
> We need to also re-draw the screen, and raising SIGWINCH, shockingly,
> Just Works.
> 
> The correct solution would be to Not Use SLang, but as a stop-gap,
> this makes TUI perf report usable.

This was in the compost pile for a long time, but I got to it, indeed
'perf report' works, the refresh after returning to it, etc.

'perf top' needs some care, but we can do it later.

About not using slang, perf started with newt, I moved to slang, there
are people suggesting we move to some more modern thing, maybe
notcurses?

- Arnaldo
 
> Signed-off-by: Ahelenia Ziemiańska <nabijaczleweli@nabijaczleweli.xyz>
> ---
> Yeah, somehow I didn't hit that in my tests, but it was relatively easy
> to trigger when I tried. A full partial write retry loop is an overkill
> here, I think, and few other places in perf actually try to resubmit
> partial writes, so.
> 
>  tools/perf/ui/browsers/annotate.c |  1 +
>  tools/perf/ui/browsers/hists.c    |  2 ++
>  tools/perf/ui/browsers/scripts.c  |  1 +
>  tools/perf/ui/tui/setup.c         | 22 ++++++++++++++++++++++
>  4 files changed, 26 insertions(+)
> 
> diff --git a/tools/perf/ui/browsers/annotate.c b/tools/perf/ui/browsers/annotate.c
> index c03fa76c02ff..6a4ffbf66c7f 100644
> --- a/tools/perf/ui/browsers/annotate.c
> +++ b/tools/perf/ui/browsers/annotate.c
> @@ -942,6 +942,7 @@ int hist_entry__tui_annotate(struct hist_entry *he, struct evsel *evsel,
>  	/* reset abort key so that it can get Ctrl-C as a key */
>  	SLang_reset_tty();
>  	SLang_init_tty(0, 0, 0);
> +	SLtty_set_suspend_state(true);
>  
>  	return map_symbol__tui_annotate(&he->ms, evsel, hbt, opts);
>  }
> diff --git a/tools/perf/ui/browsers/hists.c b/tools/perf/ui/browsers/hists.c
> index b72ee6822222..2479e6d42e7c 100644
> --- a/tools/perf/ui/browsers/hists.c
> +++ b/tools/perf/ui/browsers/hists.c
> @@ -3010,6 +3010,7 @@ static int evsel__hists_browse(struct evsel *evsel, int nr_events, const char *h
>  	/* reset abort key so that it can get Ctrl-C as a key */
>  	SLang_reset_tty();
>  	SLang_init_tty(0, 0, 0);
> +	SLtty_set_suspend_state(true);
>  
>  	if (min_pcnt)
>  		browser->min_pcnt = min_pcnt;
> @@ -3682,6 +3683,7 @@ int block_hists_tui_browse(struct block_hist *bh, struct evsel *evsel,
>  	/* reset abort key so that it can get Ctrl-C as a key */
>  	SLang_reset_tty();
>  	SLang_init_tty(0, 0, 0);
> +	SLtty_set_suspend_state(true);
>  
>  	memset(&action, 0, sizeof(action));
>  
> diff --git a/tools/perf/ui/browsers/scripts.c b/tools/perf/ui/browsers/scripts.c
> index 47d2c7a8cbe1..50d45054ed6c 100644
> --- a/tools/perf/ui/browsers/scripts.c
> +++ b/tools/perf/ui/browsers/scripts.c
> @@ -166,6 +166,7 @@ void run_script(char *cmd)
>  	printf("\033[c\033[H\033[J");
>  	fflush(stdout);
>  	SLang_init_tty(0, 0, 0);
> +	SLtty_set_suspend_state(true);
>  	SLsmg_refresh();
>  }
>  
> diff --git a/tools/perf/ui/tui/setup.c b/tools/perf/ui/tui/setup.c
> index a3b8c397c24d..09524ba04975 100644
> --- a/tools/perf/ui/tui/setup.c
> +++ b/tools/perf/ui/tui/setup.c
> @@ -2,12 +2,14 @@
>  #include <signal.h>
>  #include <stdbool.h>
>  #include <stdlib.h>
> +#include <termios.h>
>  #include <unistd.h>
>  #include <linux/kernel.h>
>  #ifdef HAVE_BACKTRACE_SUPPORT
>  #include <execinfo.h>
>  #endif
>  
> +#include "../../util/color.h"
>  #include "../../util/debug.h"
>  #include "../../perf.h"
>  #include "../browser.h"
> @@ -122,6 +124,23 @@ static void ui__signal(int sig)
>  	exit(0);
>  }
>  
> +static void ui__sigcont(int sig)
> +{
> +	static struct termios tty;
> +
> +	if (sig == SIGTSTP) {
> +		while (tcgetattr(SLang_TT_Read_FD, &tty) == -1 && errno == EINTR)
> +			;
> +		while (write(SLang_TT_Read_FD, PERF_COLOR_RESET, sizeof(PERF_COLOR_RESET) - 1) == -1 && errno == EINTR)
> +			;
> +		raise(SIGSTOP);
> +	} else {
> +		while (tcsetattr(SLang_TT_Read_FD, TCSADRAIN, &tty) == -1 && errno == EINTR)
> +			;
> +		raise(SIGWINCH);
> +	}
> +}
> +
>  int ui__init(void)
>  {
>  	int err;
> @@ -136,6 +155,7 @@ int ui__init(void)
>  	err = SLang_init_tty(-1, 0, 0);
>  	if (err < 0)
>  		goto out;
> +	SLtty_set_suspend_state(true);
>  
>  	err = SLkp_init();
>  	if (err < 0) {
> @@ -150,6 +170,8 @@ int ui__init(void)
>  	signal(SIGINT, ui__signal);
>  	signal(SIGQUIT, ui__signal);
>  	signal(SIGTERM, ui__signal);
> +	signal(SIGTSTP, ui__sigcont);
> +	signal(SIGCONT, ui__sigcont);
>  
>  	perf_error__register(&perf_tui_eops);
>  
> -- 
> 2.30.2
>
  

On Thu, Jan 4, 2024 at 1:23 PM Arnaldo Carvalho de Melo <acme@kernel.org> wrote:
>
> Em Tue, Dec 27, 2022 at 09:57:40PM +0100, Ahelenia Ziemiańska escreveu:
> > In its infinite wisdom, by default, SLang sets susp undef,
> > and this can only be un-done by calling SLtty_set_suspend_state(true).
> > After every SLang_init_tty().
> >
> > Additionally, no provisions are made for maintaining the teletype
> > attributes across suspend/continue (outside of curses emulation mode(?!),
> > which provides full support, naturally), so we need to save and restore
> > the flags ourselves, as well as reset the text colours when going under.
> > We need to also re-draw the screen, and raising SIGWINCH, shockingly,
> > Just Works.
> >
> > The correct solution would be to Not Use SLang, but as a stop-gap,
> > this makes TUI perf report usable.
>
> This was in the compost pile for a long time, but I got to it, indeed
> 'perf report' works, the refresh after returning to it, etc.
>
> 'perf top' needs some care, but we can do it later.
>
> About not using slang, perf started with newt, I moved to slang, there
> are people suggesting we move to some more modern thing, maybe
> notcurses?

Fwiw, my feeling is that doing UI stuff in C is a particular pain.
Maybe there will be a move to allow C++ in the kernel and so perf
could follow [1]. For C++ the most maintained/best text UI looks like
ftxui [2], but what I think looks best is a python library called
textual [3] that already has support for things like flamegraphs [4]
as well as having a HTML/JavaScript output/interaction option [5]. So
my feeling is that if we're rebuilding the UI we should be moving more
to python+textual than a C/C++ library that gets a fraction of the
care.

Thanks,
Ian

[1] https://www.phoronix.com/news/CPP-Linux-Kernel-2024-Discuss
[2] https://github.com/ArthurSonzogni/FTXUI
[3] https://github.com/Textualize/textual
[4] https://github.com/Textualize/textual/discussions/3390
[5] https://github.com/Textualize/textual-web

> - Arnaldo
>
> > Signed-off-by: Ahelenia Ziemiańska <nabijaczleweli@nabijaczleweli.xyz>
> > ---
> > Yeah, somehow I didn't hit that in my tests, but it was relatively easy
> > to trigger when I tried. A full partial write retry loop is an overkill
> > here, I think, and few other places in perf actually try to resubmit
> > partial writes, so.
> >
> >  tools/perf/ui/browsers/annotate.c |  1 +
> >  tools/perf/ui/browsers/hists.c    |  2 ++
> >  tools/perf/ui/browsers/scripts.c  |  1 +
> >  tools/perf/ui/tui/setup.c         | 22 ++++++++++++++++++++++
> >  4 files changed, 26 insertions(+)
> >
> > diff --git a/tools/perf/ui/browsers/annotate.c b/tools/perf/ui/browsers/annotate.c
> > index c03fa76c02ff..6a4ffbf66c7f 100644
> > --- a/tools/perf/ui/browsers/annotate.c
> > +++ b/tools/perf/ui/browsers/annotate.c
> > @@ -942,6 +942,7 @@ int hist_entry__tui_annotate(struct hist_entry *he, struct evsel *evsel,
> >       /* reset abort key so that it can get Ctrl-C as a key */
> >       SLang_reset_tty();
> >       SLang_init_tty(0, 0, 0);
> > +     SLtty_set_suspend_state(true);
> >
> >       return map_symbol__tui_annotate(&he->ms, evsel, hbt, opts);
> >  }
> > diff --git a/tools/perf/ui/browsers/hists.c b/tools/perf/ui/browsers/hists.c
> > index b72ee6822222..2479e6d42e7c 100644
> > --- a/tools/perf/ui/browsers/hists.c
> > +++ b/tools/perf/ui/browsers/hists.c
> > @@ -3010,6 +3010,7 @@ static int evsel__hists_browse(struct evsel *evsel, int nr_events, const char *h
> >       /* reset abort key so that it can get Ctrl-C as a key */
> >       SLang_reset_tty();
> >       SLang_init_tty(0, 0, 0);
> > +     SLtty_set_suspend_state(true);
> >
> >       if (min_pcnt)
> >               browser->min_pcnt = min_pcnt;
> > @@ -3682,6 +3683,7 @@ int block_hists_tui_browse(struct block_hist *bh, struct evsel *evsel,
> >       /* reset abort key so that it can get Ctrl-C as a key */
> >       SLang_reset_tty();
> >       SLang_init_tty(0, 0, 0);
> > +     SLtty_set_suspend_state(true);
> >
> >       memset(&action, 0, sizeof(action));
> >
> > diff --git a/tools/perf/ui/browsers/scripts.c b/tools/perf/ui/browsers/scripts.c
> > index 47d2c7a8cbe1..50d45054ed6c 100644
> > --- a/tools/perf/ui/browsers/scripts.c
> > +++ b/tools/perf/ui/browsers/scripts.c
> > @@ -166,6 +166,7 @@ void run_script(char *cmd)
> >       printf("\033[c\033[H\033[J");
> >       fflush(stdout);
> >       SLang_init_tty(0, 0, 0);
> > +     SLtty_set_suspend_state(true);
> >       SLsmg_refresh();
> >  }
> >
> > diff --git a/tools/perf/ui/tui/setup.c b/tools/perf/ui/tui/setup.c
> > index a3b8c397c24d..09524ba04975 100644
> > --- a/tools/perf/ui/tui/setup.c
> > +++ b/tools/perf/ui/tui/setup.c
> > @@ -2,12 +2,14 @@
> >  #include <signal.h>
> >  #include <stdbool.h>
> >  #include <stdlib.h>
> > +#include <termios.h>
> >  #include <unistd.h>
> >  #include <linux/kernel.h>
> >  #ifdef HAVE_BACKTRACE_SUPPORT
> >  #include <execinfo.h>
> >  #endif
> >
> > +#include "../../util/color.h"
> >  #include "../../util/debug.h"
> >  #include "../../perf.h"
> >  #include "../browser.h"
> > @@ -122,6 +124,23 @@ static void ui__signal(int sig)
> >       exit(0);
> >  }
> >
> > +static void ui__sigcont(int sig)
> > +{
> > +     static struct termios tty;
> > +
> > +     if (sig == SIGTSTP) {
> > +             while (tcgetattr(SLang_TT_Read_FD, &tty) == -1 && errno == EINTR)
> > +                     ;
> > +             while (write(SLang_TT_Read_FD, PERF_COLOR_RESET, sizeof(PERF_COLOR_RESET) - 1) == -1 && errno == EINTR)
> > +                     ;
> > +             raise(SIGSTOP);
> > +     } else {
> > +             while (tcsetattr(SLang_TT_Read_FD, TCSADRAIN, &tty) == -1 && errno == EINTR)
> > +                     ;
> > +             raise(SIGWINCH);
> > +     }
> > +}
> > +
> >  int ui__init(void)
> >  {
> >       int err;
> > @@ -136,6 +155,7 @@ int ui__init(void)
> >       err = SLang_init_tty(-1, 0, 0);
> >       if (err < 0)
> >               goto out;
> > +     SLtty_set_suspend_state(true);
> >
> >       err = SLkp_init();
> >       if (err < 0) {
> > @@ -150,6 +170,8 @@ int ui__init(void)
> >       signal(SIGINT, ui__signal);
> >       signal(SIGQUIT, ui__signal);
> >       signal(SIGTERM, ui__signal);
> > +     signal(SIGTSTP, ui__sigcont);
> > +     signal(SIGCONT, ui__sigcont);
> >
> >       perf_error__register(&perf_tui_eops);
> >
> > --
> > 2.30.2
> >
>
>
>
> --
>
> - Arnaldo
>