From: "Steven Rostedt (Google)" <rostedt@xxxxxxxxxxx>
Since Linux kernel 5.15 (specifically with the addition of 54357f0c9149c
("tracing: Add migrate-disabled counter to tracing output.")), the
common_preempt_count field of each event also held the "migrate-disable"
field in the most significant byte. This needs to be accounted for as when
the migrate disable field is set, it will show:
systemd--268 3d..3 15368.334398: rcu_dyntick: --= 4000000000000002 4000000000000000 0x63c
systemd--268 3d..13 15368.334399: rcu_dyntick: ++= 4000000000000000 4000000000000002 0x63c
systemd--268 3d..12 15368.334400: irq_disable: caller=ct_irq_enter_irqson+0x17 parent=0x0
systemd--268 3d..13 15368.334400: rcu_dyntick: --= 4000000000000002 4000000000000000 0x63c
systemd--268 3d..12 15368.334401: rcu_dyntick: ++= 4000000000000000 4000000000000002 0x63c
Where the events above have:
preempt-count migrate-disable
------------- ---------------
3 0
3 1
2 1
3 1
2 1
That is, in the above print of "3d..13", the '3' of the '13' is the
preempt count and the '1' is the migrate disable. But it really should be:
systemd--268 3d..3. 15368.334398: rcu_dyntick: --= 4000000000000002 4000000000000000 0x63c
systemd--268 3d..31 15368.334399: rcu_dyntick: ++= 4000000000000000 4000000000000002 0x63c
systemd--268 3d..21 15368.334400: irq_disable: caller=ct_irq_enter_irqson+0x17 parent=0x0
systemd--268 3d..31 15368.334400: rcu_dyntick: --= 4000000000000002 4000000000000000 0x63c
systemd--268 3d..21 15368.334401: rcu_dyntick: ++= 4000000000000000 4000000000000002 0x63c
Where the migrate disabled is always displayed with a '.' when zero and
its hex count when set.
Signed-off-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx>
---
src/event-parse.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/src/event-parse.c b/src/event-parse.c
index 18db7fcb456d..e655087dad60 100644
--- a/src/event-parse.c
+++ b/src/event-parse.c
@@ -6768,8 +6768,13 @@ static void data_latency_format(struct tep_handle *tep, struct trace_seq *s,
(hardirq && softirq) ? 'H' :
hardirq ? 'h' : softirq ? 's' : '.');
- if (pc)
- trace_seq_printf(&sq, "%x", pc);
+ if (pc & 0xf)
+ trace_seq_printf(&sq, "%x", pc & 0xf);
+ else
+ trace_seq_printf(&sq, ".");
+
+ if (pc & 0xf0)
+ trace_seq_printf(&sq, "%x", pc >> 4);
else
trace_seq_printf(&sq, ".");
--
2.35.1
|