rtla/timerlat: Simplify "no value" printing on top

JIRA: https://issues.redhat.com/browse/RHEL-50869

commit 5f07693
Author: Daniel Bristot de Oliveira <bristot@kernel.org>
Date:   Wed Apr 24 16:36:50 2024 +0200

    rtla/timerlat: Simplify "no value" printing on top

    Instead of printing three times the same output, print it only once,
    reducing lines and being sure that all no values have the same length.

    It also fixes an extra '\n' when running the with kernel threads, like
    here:

         =============== %< ==============
                                          Timer Latency

       0 00:00:01   |          IRQ Timer Latency (us)        |         Thread Timer Latency (us)
     CPU COUNT      |      cur       min       avg       max |      cur       min       avg       max
       2 #0         |        -         -         -         - |      161       161       161       161
       3 #0         |        -         -         -         - |      161       161       161       161
       8 #1         |       54        54        54        54 |        -         -         -         -'\n'

     ---------------|----------------------------------------|---------------------------------------
     ALL #1      e0 |                 54        54        54 |                161       161       161
         =============== %< ==============

    This '\n' should have been removed with the user-space support that
    added another '\n' if not running with kernel threads.

    Link: https://lkml.kernel.org/r/0a4d8085e7cd706733a5dc10a81ca38b82bd4992.1713968967.git.bristot@kernel.org

    Cc: stable@vger.kernel.org
    Cc: Jonathan Corbet <corbet@lwn.net>
    Cc: Juri Lelli <juri.lelli@redhat.com>
    Fixes: cdca4f4 ("rtla/timerlat_top: Add timerlat user-space support")
    Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>

Signed-off-by: Luis Claudio R. Goncalves <lgoncalv@redhat.com>

Author: lclaudio

tools/tracing/rtla/src/timerlat_top.c

@@ -212,6 +212,8 @@ static void timerlat_top_header(struct osnoise_tool *top)
 	trace_seq_printf(s, "\n");
 }
 
+static const char *no_value = "        -";
+
 /*
  * timerlat_top_print - prints the output of a given CPU
  */
@@ -239,10 +241,7 @@ static void timerlat_top_print(struct osnoise_tool *top, int cpu)
 	trace_seq_printf(s, "%3d #%-9d |", cpu, cpu_data->irq_count);
 
 	if (!cpu_data->irq_count) {
-		trace_seq_printf(s, "        - ");
-		trace_seq_printf(s, "        - ");
-		trace_seq_printf(s, "        - ");
-		trace_seq_printf(s, "        - |");
+		trace_seq_printf(s, "%s %s %s %s |", no_value, no_value, no_value, no_value);
 	} else {
 		trace_seq_printf(s, "%9llu ", cpu_data->cur_irq / params->output_divisor);
 		trace_seq_printf(s, "%9llu ", cpu_data->min_irq / params->output_divisor);
@@ -251,10 +250,7 @@ static void timerlat_top_print(struct osnoise_tool *top, int cpu)
 	}
 
 	if (!cpu_data->thread_count) {
-		trace_seq_printf(s, "        - ");
-		trace_seq_printf(s, "        - ");
-		trace_seq_printf(s, "        - ");
-		trace_seq_printf(s, "        -\n");
+		trace_seq_printf(s, "%s %s %s %s", no_value, no_value, no_value, no_value);
 	} else {
 		trace_seq_printf(s, "%9llu ", cpu_data->cur_thread / divisor);
 		trace_seq_printf(s, "%9llu ", cpu_data->min_thread / divisor);
@@ -271,10 +267,7 @@ static void timerlat_top_print(struct osnoise_tool *top, int cpu)
 	trace_seq_printf(s, " |");
 
 	if (!cpu_data->user_count) {
-		trace_seq_printf(s, "        - ");
-		trace_seq_printf(s, "        - ");
-		trace_seq_printf(s, "        - ");
-		trace_seq_printf(s, "        -\n");
+		trace_seq_printf(s, "%s %s %s %s\n", no_value, no_value, no_value, no_value);
 	} else {
 		trace_seq_printf(s, "%9llu ", cpu_data->cur_user / divisor);
 		trace_seq_printf(s, "%9llu ", cpu_data->min_user / divisor);