Re: [PATCH] Speed up "gdb -tui" output

Doug Evans
2015-01-07T21:59:14Z

Doug Evans writes:
> Seems like the main source of the problem would be gdb_stdout,
> so let's try to fix that first and go from there.

Here's a prototype.
I left fflush (stdout) in to be conservative.

Does this resolve the performance issues you're seeing well enough?

2015-01-07 Doug Evans <dje@google.com>

PR tui/17810
* tui/tui-command.c (tui_refresh_cmd_win): New function.
* tui/tui-command.c (tui_refresh_cmd_win): Declare.
* tui/tui-file.c: #include tui/tui-command.h.
(tui_file_fputs): Refresh command window if stream is not gdb_stdout.
(tui_file_flush): Refresh command window if stream is gdb_stdout or
gdb_stderr.
* tui/tui-io.c (tui_puts): Remove call to wrefresh, fflush.
(tui_readline_output): Call tui_refresh_cmd_win.
(print_filename): Ditto.
(tui_rl_display_match_list): Ditto.

diff --git a/gdb/tui/tui-command.c b/gdb/tui/tui-command.c
index d1a5ddb..6d98db2 100644
--- a/gdb/tui/tui-command.c
+++ b/gdb/tui/tui-command.c
@@ -129,3 +129,18 @@ tui_dispatch_ctrl_char (unsigned int ch)
return c;
}
}
+
+/* Refresh the command window. */
+
+void
+tui_refresh_cmd_win (void)
+{
+ WINDOW *w = TUI_CMD_WIN->generic.handle;
+
+ wrefresh (w);
+
+ /* FIXME: It's not clear why this is here.
+ It was present in the original tui_puts code and is kept in order to
+ not introduce some subtle breakage. */
+ fflush (stdout);
+}
diff --git a/gdb/tui/tui-command.h b/gdb/tui/tui-command.h
index 8cc5be4..174ba58 100644
--- a/gdb/tui/tui-command.h
+++ b/gdb/tui/tui-command.h
@@ -24,4 +24,6 @@

extern unsigned int tui_dispatch_ctrl_char (unsigned int);

+extern void tui_refresh_cmd_win (void);
+
#endif
diff --git a/gdb/tui/tui-file.c b/gdb/tui/tui-file.c
index b32cfa6..02d9082 100644
--- a/gdb/tui/tui-file.c
+++ b/gdb/tui/tui-file.c
@@ -20,7 +20,7 @@
#include "ui-file.h"
#include "tui/tui-file.h"
#include "tui/tui-io.h"
-
+#include "tui/tui-command.h"
#include "tui.h"

/* A ``struct ui_file'' that is compatible with all the legacy
@@ -179,6 +179,10 @@ tui_file_fputs (const char *linebuffer, struct ui_file *file)
else
{
tui_puts (linebuffer);
+ /* gdb_stdout is buffered, and the caller must gdb_flush it at
+ appropriate times. Other streams are not so buffered. */
+ if (file != gdb_stdout)
+ tui_refresh_cmd_win ();
}
}

@@ -239,6 +243,12 @@ tui_file_flush (struct ui_file *file)
case astring:
break;
case afile:
+ /* There is also gdb_stdlog, gdb_stdtarg, gdb_stdtargerr, but
+ tui_setup_io maps those to gdb_stderr. OTOH, do we need to make
+ this conditional? */
+ if (file == gdb_stdout
+ || file == gdb_stderr)
+ tui_refresh_cmd_win ();
fflush (stream->ts_filestream);
break;
}
diff --git a/gdb/tui/tui-io.c b/gdb/tui/tui-io.c
index 233e7a6..c3ab612 100644
--- a/gdb/tui/tui-io.c
+++ b/gdb/tui/tui-io.c
@@ -158,7 +158,10 @@ tui_putc (char c)
tui_puts (buf);
}

-/* Print the string in the curses command window. */
+/* Print the string in the curses command window.
+ The output is buffered. It is up to the caller to refresh the screen
+ if necessary. */
+
void
tui_puts (const char *string)
{
@@ -187,10 +190,6 @@ tui_puts (const char *string)
TUI_CMD_WIN->detail.command_info.curch);
TUI_CMD_WIN->detail.command_info.start_line
= TUI_CMD_WIN->detail.command_info.cur_line;
-
- /* We could defer the following. */
- wrefresh (w);
- fflush (stdout);
}

/* Readline callback.
@@ -316,6 +315,7 @@ tui_readline_output (int error, gdb_client_data data)
{
buf[size] = 0;
tui_puts (buf);
+ tui_refresh_cmd_win ();
}
}
#endif
@@ -367,6 +367,7 @@ print_filename (const char *to_print, const char *full_pathname)
{
PUTX (*s);
}
+ tui_refresh_cmd_win ();
return printed_len;
}

@@ -425,6 +426,7 @@ tui_rl_display_match_list (char **matches, int len, int max)
if (get_y_or_n () == 0)
{
tui_puts ("\n");
+ tui_refresh_cmd_win ();
return;
}
}