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Date: Tue, 20 Jan 2009 16:52:36 -0800 (PST)
From: Frederic Weisbecker <fweisbec@...il.com>
To: Steven Rostedt <rostedt@...dmis.org>
Cc: Ingo Molnar <mingo@...e.hu>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
Arnaldo Carvalho de Melo <acme@...stprotocols.net>,
Frederic Weisbecker <fweisbec@...il.com>
Subject: [PATCH] tracing/ftrace: add an option to not print the context info for events
Impact: make trace_event more convenient for tracers
All tracers (for the moment) that use the struct trace_event want to have
the context info printed before their own output: the pid/cmdline, cpu, and timestamp.
But some other tracers that want to implement their trace_event callbacks will
not necessary need these information.
This patch adds a new default-enabled trace option: TRACE_ITER_CONTEXT_INFO
When disabled through:
echo nocontext-info > /debugfs/tracing/trace_options
The pid, cpu and timestamps headers will not be printed.
IE with the sched_switch tracer with context-info (default):
bash-2935 [001] 100.356561: 2935:120:S ==> [001] 0:140:R <idle>
<idle>-0 [000] 100.412804: 0:140:R + [000] 11:115:S events/0
<idle>-0 [000] 100.412816: 0:140:R ==> [000] 11:115:R events/0
events/0-11 [000] 100.412829: 11:115:S ==> [000] 0:140:R <idle>
Without context-info:
2935:120:S ==> [001] 0:140:R <idle>
0:140:R + [000] 11:115:S events/0
0:140:R ==> [000] 11:115:R events/0
11:115:S ==> [000] 0:140:R <idle>
A tracer can disable it at runtime by clearing the bit TRACE_ITER_CONTEXT_INFO in trace_flags.
Signed-off-by: Frederic Weisbecker <fweisbec@...il.com>
---
kernel/trace/trace.c | 61 ++++++++++++++++++++++++++++---------------------
kernel/trace/trace.h | 3 +-
2 files changed, 37 insertions(+), 27 deletions(-)
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 220c264..a59ba48 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -227,7 +227,7 @@ static DECLARE_WAIT_QUEUE_HEAD(trace_wait);
/* trace_flags holds trace_options default values */
unsigned long trace_flags = TRACE_ITER_PRINT_PARENT | TRACE_ITER_PRINTK |
- TRACE_ITER_ANNOTATE;
+ TRACE_ITER_ANNOTATE | TRACE_ITER_CONTEXT_INFO;
/**
* trace_wake_up - wake up tasks waiting for trace input
@@ -285,6 +285,7 @@ static const char *trace_options[] = {
"userstacktrace",
"sym-userobj",
"printk-msg-only",
+ "context-info",
NULL
};
@@ -1487,21 +1488,23 @@ static enum print_line_t print_trace_fmt(struct trace_iterator *iter)
test_cpu_buff_start(iter);
- comm = trace_find_cmdline(iter->ent->pid);
-
- t = ns2usecs(iter->ts);
- usec_rem = do_div(t, 1000000ULL);
- secs = (unsigned long)t;
-
- ret = trace_seq_printf(s, "%16s-%-5d ", comm, entry->pid);
- if (!ret)
- return TRACE_TYPE_PARTIAL_LINE;
- ret = trace_seq_printf(s, "[%03d] ", iter->cpu);
- if (!ret)
- return TRACE_TYPE_PARTIAL_LINE;
- ret = trace_seq_printf(s, "%5lu.%06lu: ", secs, usec_rem);
- if (!ret)
- return TRACE_TYPE_PARTIAL_LINE;
+ if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
+ comm = trace_find_cmdline(iter->ent->pid);
+
+ t = ns2usecs(iter->ts);
+ usec_rem = do_div(t, 1000000ULL);
+ secs = (unsigned long)t;
+
+ ret = trace_seq_printf(s, "%16s-%-5d ", comm, entry->pid);
+ if (!ret)
+ return TRACE_TYPE_PARTIAL_LINE;
+ ret = trace_seq_printf(s, "[%03d] ", iter->cpu);
+ if (!ret)
+ return TRACE_TYPE_PARTIAL_LINE;
+ ret = trace_seq_printf(s, "%5lu.%06lu: ", secs, usec_rem);
+ if (!ret)
+ return TRACE_TYPE_PARTIAL_LINE;
+ }
event = ftrace_find_event(entry->type);
if (event && event->trace) {
@@ -1526,10 +1529,12 @@ static enum print_line_t print_raw_fmt(struct trace_iterator *iter)
entry = iter->ent;
- ret = trace_seq_printf(s, "%d %d %llu ",
- entry->pid, iter->cpu, iter->ts);
- if (!ret)
- return TRACE_TYPE_PARTIAL_LINE;
+ if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
+ ret = trace_seq_printf(s, "%d %d %llu ",
+ entry->pid, iter->cpu, iter->ts);
+ if (!ret)
+ return TRACE_TYPE_PARTIAL_LINE;
+ }
event = ftrace_find_event(entry->type);
if (event && event->raw) {
@@ -1554,9 +1559,11 @@ static enum print_line_t print_hex_fmt(struct trace_iterator *iter)
entry = iter->ent;
- SEQ_PUT_HEX_FIELD_RET(s, entry->pid);
- SEQ_PUT_HEX_FIELD_RET(s, iter->cpu);
- SEQ_PUT_HEX_FIELD_RET(s, iter->ts);
+ if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
+ SEQ_PUT_HEX_FIELD_RET(s, entry->pid);
+ SEQ_PUT_HEX_FIELD_RET(s, iter->cpu);
+ SEQ_PUT_HEX_FIELD_RET(s, iter->ts);
+ }
event = ftrace_find_event(entry->type);
if (event && event->hex)
@@ -1591,9 +1598,11 @@ static enum print_line_t print_bin_fmt(struct trace_iterator *iter)
entry = iter->ent;
- SEQ_PUT_FIELD_RET(s, entry->pid);
- SEQ_PUT_FIELD_RET(s, entry->cpu);
- SEQ_PUT_FIELD_RET(s, iter->ts);
+ if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
+ SEQ_PUT_FIELD_RET(s, entry->pid);
+ SEQ_PUT_FIELD_RET(s, entry->cpu);
+ SEQ_PUT_FIELD_RET(s, iter->ts);
+ }
event = ftrace_find_event(entry->type);
if (event && event->binary)
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index b96037d..282248e 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -590,7 +590,8 @@ enum trace_iterator_flags {
TRACE_ITER_ANNOTATE = 0x2000,
TRACE_ITER_USERSTACKTRACE = 0x4000,
TRACE_ITER_SYM_USEROBJ = 0x8000,
- TRACE_ITER_PRINTK_MSGONLY = 0x10000
+ TRACE_ITER_PRINTK_MSGONLY = 0x10000,
+ TRACE_ITER_CONTEXT_INFO = 0x20000 /* Print pid/cpu/time */
};
/*
--
1.6.0.4
--
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