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Date: Fri, 10 May 2024 12:26:05 -0400
From: John Kacur <jkacur@...hat.com>
To: Daniel Bristot de Oliveria <bristot@...nel.org>,
Steven Rostedt <rostedt@...dmis.org>,
linux-trace-devel@...r.kernel.org
Cc: lkml <linux-kernel@...r.kernel.org>,
stable@...r.kernel.org,
John Kacur <jkacur@...hat.com>
Subject: [PATCH] Fix reporting when a cpu count is 0
On short runs it is possible to get no samples on a cpu, like this
rtla timerlat hist -P f:95 -u -c0-11 -E3500 -T50'
Index IRQ-001 Thr-001 Usr-001 IRQ-002 Thr-002 Usr-002
2 1 0 0 0 0 0
33 0 1 0 0 0 0
36 0 0 1 0 0 0
49 0 0 0 1 0 0
52 0 0 0 0 1 0
over: 0 0 0 0 0 0
count: 1 1 1 1 1 0
min: 2 33 36 49 52 18446744073709551615
avg: 2 33 36 49 52 -
max: 2 33 36 49 52 0
rtla timerlat hit stop tracing
IRQ handler delay: (exit from idle) 48.21 us (91.09 %)
IRQ latency: 49.11 us
Timerlat IRQ duration: 2.17 us (4.09 %)
Blocking thread: 1.01 us (1.90 %)
swapper/2:0 1.01 us
------------------------------------------------------------------------
Thread latency: 52.93 us (100%)Max timerlat IRQ latency from idle: 49.11 us in cpu 2
Note, the value 18446744073709551615 is the same as ~0
Fix this by reporting no results for the min, avg and max if the count
is 0
This solution came from Daniel Bristot de Oliveria <bristot@...nel.org>
Fixes: 1eeb6328e8b3 ("rtla/timerlat: Add timerlat hist mode")
Tested-by: John Kacur <jkacur@...hat.com>
Signed-off-by: John Kacur <jkacur@...hat.com>
---
tools/tracing/rtla/src/timerlat_hist.c | 60 ++++++++++++++++++--------
1 file changed, 42 insertions(+), 18 deletions(-)
diff --git a/tools/tracing/rtla/src/timerlat_hist.c b/tools/tracing/rtla/src/timerlat_hist.c
index 8bd51aab6513..5b869caed10d 100644
--- a/tools/tracing/rtla/src/timerlat_hist.c
+++ b/tools/tracing/rtla/src/timerlat_hist.c
@@ -324,17 +324,29 @@ timerlat_print_summary(struct timerlat_hist_params *params,
if (!data->hist[cpu].irq_count && !data->hist[cpu].thread_count)
continue;
- if (!params->no_irq)
- trace_seq_printf(trace->seq, "%9llu ",
- data->hist[cpu].min_irq);
+ if (!params->no_irq) {
+ if (data->hist[cpu].irq_count)
+ trace_seq_printf(trace->seq, "%9llu ",
+ data->hist[cpu].min_irq);
+ else
+ trace_seq_printf(trace->seq, " - ");
+ }
- if (!params->no_thread)
- trace_seq_printf(trace->seq, "%9llu ",
- data->hist[cpu].min_thread);
+ if (!params->no_thread) {
+ if (data->hist[cpu].thread_count)
+ trace_seq_printf(trace->seq, "%9llu ",
+ data->hist[cpu].min_thread);
+ else
+ trace_seq_printf(trace->seq, " - ");
+ }
- if (params->user_hist)
- trace_seq_printf(trace->seq, "%9llu ",
- data->hist[cpu].min_user);
+ if (params->user_hist) {
+ if (data->hist[cpu].user_count)
+ trace_seq_printf(trace->seq, "%9llu ",
+ data->hist[cpu].min_user);
+ else
+ trace_seq_printf(trace->seq, " - ");
+ }
}
trace_seq_printf(trace->seq, "\n");
@@ -384,17 +396,29 @@ timerlat_print_summary(struct timerlat_hist_params *params,
if (!data->hist[cpu].irq_count && !data->hist[cpu].thread_count)
continue;
- if (!params->no_irq)
- trace_seq_printf(trace->seq, "%9llu ",
- data->hist[cpu].max_irq);
+ if (!params->no_irq) {
+ if (data->hist[cpu].irq_count)
+ trace_seq_printf(trace->seq, "%9llu ",
+ data->hist[cpu].max_irq);
+ else
+ trace_seq_printf(trace->seq, " - ");
+ }
- if (!params->no_thread)
- trace_seq_printf(trace->seq, "%9llu ",
- data->hist[cpu].max_thread);
+ if (!params->no_thread) {
+ if (data->hist[cpu].thread_count)
+ trace_seq_printf(trace->seq, "%9llu ",
+ data->hist[cpu].max_thread);
+ else
+ trace_seq_printf(trace->seq, " - ");
+ }
- if (params->user_hist)
- trace_seq_printf(trace->seq, "%9llu ",
- data->hist[cpu].max_user);
+ if (params->user_hist) {
+ if (data->hist[cpu].user_count)
+ trace_seq_printf(trace->seq, "%9llu ",
+ data->hist[cpu].max_user);
+ else
+ trace_seq_printf(trace->seq, " - ");
+ }
}
trace_seq_printf(trace->seq, "\n");
trace_seq_do_printf(trace->seq);
--
2.44.0
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