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sched/debug: Adjust newlines for better alignment
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Scheduler debug stats include newlines that display out of alignment
when prefixed by timestamps.  For example, the dmesg utility:

  % echo t > /proc/sysrq-trigger
  % dmesg
  ...
  [   83.124251]
  runnable tasks:
   S           task   PID         tree-key  switches  prio     wait-time
  sum-exec        sum-sleep
  -----------------------------------------------------------------------------------------------------------

At the same time, some syslog utilities (like rsyslog by default) don't
like the additional newlines control characters, saving lines like this
to /var/log/messages:

  Mar 16 16:02:29 localhost kernel: #012runnable tasks:anholt#12 S           task   PID         tree-key ...
                                    ^^^^               ^^^^
Clean these up by moving newline characters to their own SEQ_printf
invocation.  This leaves the /proc/sched_debug unchanged, but brings the
entire output into alignment when prefixed:

  % echo t > /proc/sysrq-trigger
  % dmesg
  ...
  [   62.410368] runnable tasks:
  [   62.410368]  S           task   PID         tree-key  switches  prio     wait-time             sum-exec        sum-sleep
  [   62.410369] -----------------------------------------------------------------------------------------------------------
  [   62.410369]  I  kworker/u12:0     5      1932.215593       332   120         0.000000         3.621252         0.000000 0 0 /

and no escaped control characters from rsyslog in /var/log/messages:

  Mar 16 16:15:06 localhost kernel: runnable tasks:
  Mar 16 16:15:06 localhost kernel: S           task   PID         tree-key  ...

Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1521484555-8620-3-git-send-email-joe.lawrence@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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joe-lawrence authored and Ingo Molnar committed Mar 20, 2018
1 parent a8c024c commit e9ca267
Showing 1 changed file with 16 additions and 11 deletions.
27 changes: 16 additions & 11 deletions kernel/sched/debug.c
Original file line number Diff line number Diff line change
Expand Up @@ -501,12 +501,12 @@ static void print_rq(struct seq_file *m, struct rq *rq, int rq_cpu)
{
struct task_struct *g, *p;

SEQ_printf(m,
"\nrunnable tasks:\n"
" S task PID tree-key switches prio"
" wait-time sum-exec sum-sleep\n"
"-------------------------------------------------------"
"----------------------------------------------------\n");
SEQ_printf(m, "\n");
SEQ_printf(m, "runnable tasks:\n");
SEQ_printf(m, " S task PID tree-key switches prio"
" wait-time sum-exec sum-sleep\n");
SEQ_printf(m, "-------------------------------------------------------"
"----------------------------------------------------\n");

rcu_read_lock();
for_each_process_thread(g, p) {
Expand All @@ -527,9 +527,11 @@ void print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq)
unsigned long flags;

#ifdef CONFIG_FAIR_GROUP_SCHED
SEQ_printf(m, "\ncfs_rq[%d]:%s\n", cpu, task_group_path(cfs_rq->tg));
SEQ_printf(m, "\n");
SEQ_printf(m, "cfs_rq[%d]:%s\n", cpu, task_group_path(cfs_rq->tg));
#else
SEQ_printf(m, "\ncfs_rq[%d]:\n", cpu);
SEQ_printf(m, "\n");
SEQ_printf(m, "cfs_rq[%d]:\n", cpu);
#endif
SEQ_printf(m, " .%-30s: %Ld.%06ld\n", "exec_clock",
SPLIT_NS(cfs_rq->exec_clock));
Expand Down Expand Up @@ -595,9 +597,11 @@ void print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq)
void print_rt_rq(struct seq_file *m, int cpu, struct rt_rq *rt_rq)
{
#ifdef CONFIG_RT_GROUP_SCHED
SEQ_printf(m, "\nrt_rq[%d]:%s\n", cpu, task_group_path(rt_rq->tg));
SEQ_printf(m, "\n");
SEQ_printf(m, "rt_rq[%d]:%s\n", cpu, task_group_path(rt_rq->tg));
#else
SEQ_printf(m, "\nrt_rq[%d]:\n", cpu);
SEQ_printf(m, "\n");
SEQ_printf(m, "rt_rq[%d]:\n", cpu);
#endif

#define P(x) \
Expand All @@ -624,7 +628,8 @@ void print_dl_rq(struct seq_file *m, int cpu, struct dl_rq *dl_rq)
{
struct dl_bw *dl_bw;

SEQ_printf(m, "\ndl_rq[%d]:\n", cpu);
SEQ_printf(m, "\n");
SEQ_printf(m, "dl_rq[%d]:\n", cpu);

#define PU(x) \
SEQ_printf(m, " .%-30s: %lu\n", #x, (unsigned long)(dl_rq->x))
Expand Down

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