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Message-ID: <20230117152236.167046397@goodmis.org>
Date: Tue, 17 Jan 2023 10:21:29 -0500
From: Steven Rostedt <rostedt@...dmis.org>
To: linux-kernel@...r.kernel.org, linux-trace-kernel@...r.kernel.org
Cc: Masami Hiramatsu <mhiramat@...nel.org>,
Andrew Morton <akpm@...ux-foundation.org>,
Tom Zanussi <zanussi@...nel.org>,
Ross Zwisler <zwisler@...gle.com>,
Ching-lin Yu <chinglinyu@...gle.com>
Subject: [PATCH 4/6 v2] tracing/histogram: Add stacktrace type
From: "Steven Rostedt (Google)" <rostedt@...dmis.org>
Now that stacktraces can be part of synthetic events, allow a key to be
typed as a stacktrace.
# cd /sys/kernel/tracing
# echo 's:block_lat u64 delta; unsigned long stack[];' >> dynamic_events
# echo 'hist:keys=next_pid:ts=common_timestamp.usecs,st=stacktrace if prev_state == 2' >> events/sched/sched_switch/trigger
# echo 'hist:keys=prev_pid:delta=common_timestamp.usecs-$ts,st2=$st:onmatch(sched.sched_switch).trace(block_lat,$delta,$st2)' >> events/sched/sched_switch/trigger
# echo 'hist:keys=delta.buckets=100,stack.stacktrace:sort=delta' > events/synthetic/block_lat/trigger
# cat events/synthetic/block_lat/hist
# event histogram
#
# trigger info: hist:keys=delta.buckets=100,stacktrace:vals=hitcount:sort=delta.buckets=100:size=2048 [active]
#
{ delta: ~ 0-99, stacktrace:
event_hist_trigger+0x464/0x480
event_triggers_call+0x52/0xe0
trace_event_buffer_commit+0x193/0x250
trace_event_raw_event_sched_switch+0xfc/0x150
__traceiter_sched_switch+0x41/0x60
__schedule+0x448/0x7b0
schedule_idle+0x26/0x40
cpu_startup_entry+0x19/0x20
start_secondary+0xed/0xf0
secondary_startup_64_no_verify+0xe0/0xeb
} hitcount: 6
{ delta: ~ 0-99, stacktrace:
event_hist_trigger+0x464/0x480
event_triggers_call+0x52/0xe0
trace_event_buffer_commit+0x193/0x250
trace_event_raw_event_sched_switch+0xfc/0x150
__traceiter_sched_switch+0x41/0x60
__schedule+0x448/0x7b0
schedule_idle+0x26/0x40
cpu_startup_entry+0x19/0x20
__pfx_kernel_init+0x0/0x10
arch_call_rest_init+0xa/0x24
start_kernel+0x964/0x98d
secondary_startup_64_no_verify+0xe0/0xeb
} hitcount: 3
{ delta: ~ 0-99, stacktrace:
event_hist_trigger+0x464/0x480
event_triggers_call+0x52/0xe0
trace_event_buffer_commit+0x193/0x250
trace_event_raw_event_sched_switch+0xfc/0x150
__traceiter_sched_switch+0x41/0x60
__schedule+0x448/0x7b0
schedule+0x5a/0xb0
worker_thread+0xaf/0x380
kthread+0xe9/0x110
ret_from_fork+0x2c/0x50
} hitcount: 1
{ delta: ~ 100-199, stacktrace:
event_hist_trigger+0x464/0x480
event_triggers_call+0x52/0xe0
trace_event_buffer_commit+0x193/0x250
trace_event_raw_event_sched_switch+0xfc/0x150
__traceiter_sched_switch+0x41/0x60
__schedule+0x448/0x7b0
schedule_idle+0x26/0x40
cpu_startup_entry+0x19/0x20
start_secondary+0xed/0xf0
secondary_startup_64_no_verify+0xe0/0xeb
} hitcount: 15
[..]
{ delta: ~ 8500-8599, stacktrace:
event_hist_trigger+0x464/0x480
event_triggers_call+0x52/0xe0
trace_event_buffer_commit+0x193/0x250
trace_event_raw_event_sched_switch+0xfc/0x150
__traceiter_sched_switch+0x41/0x60
__schedule+0x448/0x7b0
schedule_idle+0x26/0x40
cpu_startup_entry+0x19/0x20
start_secondary+0xed/0xf0
secondary_startup_64_no_verify+0xe0/0xeb
} hitcount: 1
Totals:
Hits: 89
Entries: 11
Dropped: 0
Signed-off-by: Steven Rostedt (Google) <rostedt@...dmis.org>
---
kernel/trace/trace_events_hist.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index 599c056b6048..888b7a394ce5 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -1716,6 +1716,8 @@ static const char *get_hist_field_flags(struct hist_field *hist_field)
flags_str = "percent";
else if (hist_field->flags & HIST_FIELD_FL_GRAPH)
flags_str = "graph";
+ else if (hist_field->flags & HIST_FIELD_FL_STACKTRACE)
+ flags_str = "stacktrace";
return flags_str;
}
@@ -2312,6 +2314,8 @@ parse_field(struct hist_trigger_data *hist_data, struct trace_event_file *file,
*flags |= HIST_FIELD_FL_EXECNAME;
else if (strcmp(modifier, "syscall") == 0)
*flags |= HIST_FIELD_FL_SYSCALL;
+ else if (strcmp(modifier, "stacktrace") == 0)
+ *flags |= HIST_FIELD_FL_STACKTRACE;
else if (strcmp(modifier, "log2") == 0)
*flags |= HIST_FIELD_FL_LOG2;
else if (strcmp(modifier, "usecs") == 0)
--
2.39.0
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