From: Steven Rostedt <rostedt@kernel.org>
To: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Andrew Morton <akpm@linux-foundation.org>
Subject: [PATCH 3/4] tracing: Have function graph tracer option sleep-time be per instance
Date: Fri, 14 Nov 2025 14:22:32 -0500 [thread overview]
Message-ID: <20251114192318.950255167@kernel.org> (raw)
In-Reply-To: 20251114192229.829042264@kernel.org
From: Steven Rostedt <rostedt@goodmis.org>
Currently the option to have function graph tracer to ignore time spent
when a task is sleeping is global when the interface is per-instance.
Changing the value in one instance will affect the results of another
instance that is also running the function graph tracer. This can lead to
confusing results.
Fixes: c132be2c4fcc1 ("function_graph: Have the instances use their own ftrace_ops for filtering")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
kernel/trace/fgraph.c | 10 +----
kernel/trace/ftrace.c | 4 +-
kernel/trace/trace.h | 5 +--
kernel/trace/trace_functions_graph.c | 64 +++++++++++++++++++++++-----
4 files changed, 60 insertions(+), 23 deletions(-)
diff --git a/kernel/trace/fgraph.c b/kernel/trace/fgraph.c
index 484ad7a18463..7fb9b169d6d4 100644
--- a/kernel/trace/fgraph.c
+++ b/kernel/trace/fgraph.c
@@ -498,9 +498,6 @@ void *fgraph_retrieve_parent_data(int idx, int *size_bytes, int depth)
return get_data_type_data(current, offset);
}
-/* Both enabled by default (can be cleared by function_graph tracer flags */
-bool fgraph_sleep_time = true;
-
#ifdef CONFIG_DYNAMIC_FTRACE
/*
* archs can override this function if they must do something
@@ -1023,11 +1020,6 @@ void fgraph_init_ops(struct ftrace_ops *dst_ops,
#endif
}
-void ftrace_graph_sleep_time_control(bool enable)
-{
- fgraph_sleep_time = enable;
-}
-
/*
* Simply points to ftrace_stub, but with the proper protocol.
* Defined by the linker script in linux/vmlinux.lds.h
@@ -1098,7 +1090,7 @@ ftrace_graph_probe_sched_switch(void *ignore, bool preempt,
* Does the user want to count the time a function was asleep.
* If so, do not update the time stamps.
*/
- if (fgraph_sleep_time)
+ if (!fgraph_no_sleep_time)
return;
timestamp = trace_clock_local();
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index ab601cd9638b..7c3bbebeec7a 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -862,6 +862,8 @@ static int profile_graph_entry(struct ftrace_graph_ent *trace,
return 1;
}
+bool fprofile_no_sleep_time;
+
static void profile_graph_return(struct ftrace_graph_ret *trace,
struct fgraph_ops *gops,
struct ftrace_regs *fregs)
@@ -887,7 +889,7 @@ static void profile_graph_return(struct ftrace_graph_ret *trace,
calltime = rettime - profile_data->calltime;
- if (!fgraph_sleep_time) {
+ if (fprofile_no_sleep_time) {
if (current->ftrace_sleeptime)
calltime -= current->ftrace_sleeptime - profile_data->sleeptime;
}
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 41b416a22450..58be6d741d72 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -943,8 +943,6 @@ static __always_inline bool ftrace_hash_empty(struct ftrace_hash *hash)
#define TRACE_GRAPH_PRINT_FILL_SHIFT 28
#define TRACE_GRAPH_PRINT_FILL_MASK (0x3 << TRACE_GRAPH_PRINT_FILL_SHIFT)
-extern void ftrace_graph_sleep_time_control(bool enable);
-
#ifdef CONFIG_FUNCTION_PROFILER
extern void ftrace_graph_graph_time_control(bool enable);
#else
@@ -1115,7 +1113,8 @@ static inline void ftrace_graph_addr_finish(struct fgraph_ops *gops, struct ftra
#endif /* CONFIG_DYNAMIC_FTRACE */
extern unsigned int fgraph_max_depth;
-extern bool fgraph_sleep_time;
+extern unsigned int fgraph_no_sleep_time;
+extern bool fprofile_no_sleep_time;
static inline bool
ftrace_graph_ignore_func(struct fgraph_ops *gops, struct ftrace_graph_ent *trace)
diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
index 53adbe4bfedb..12315eb65925 100644
--- a/kernel/trace/trace_functions_graph.c
+++ b/kernel/trace/trace_functions_graph.c
@@ -19,6 +19,9 @@
/* When set, irq functions might be ignored */
static int ftrace_graph_skip_irqs;
+/* Do not record function time when task is sleeping */
+unsigned int fgraph_no_sleep_time;
+
struct fgraph_cpu_data {
pid_t last_pid;
int depth;
@@ -239,13 +242,14 @@ static int graph_entry(struct ftrace_graph_ent *trace,
if (ftrace_graph_ignore_irqs(tr))
return 0;
- if (fgraph_sleep_time) {
- /* Only need to record the calltime */
- ftimes = fgraph_reserve_data(gops->idx, sizeof(ftimes->calltime));
- } else {
+ if (fgraph_no_sleep_time &&
+ !tracer_flags_is_set(tr, TRACE_GRAPH_SLEEP_TIME)) {
ftimes = fgraph_reserve_data(gops->idx, sizeof(*ftimes));
if (ftimes)
ftimes->sleeptime = current->ftrace_sleeptime;
+ } else {
+ /* Only need to record the calltime */
+ ftimes = fgraph_reserve_data(gops->idx, sizeof(ftimes->calltime));
}
if (!ftimes)
return 0;
@@ -331,11 +335,15 @@ void __trace_graph_return(struct trace_array *tr,
trace_buffer_unlock_commit_nostack(buffer, event);
}
-static void handle_nosleeptime(struct ftrace_graph_ret *trace,
+static void handle_nosleeptime(struct trace_array *tr,
+ struct ftrace_graph_ret *trace,
struct fgraph_times *ftimes,
int size)
{
- if (fgraph_sleep_time || size < sizeof(*ftimes))
+ if (size < sizeof(*ftimes))
+ return;
+
+ if (!fgraph_no_sleep_time || tracer_flags_is_set(tr, TRACE_GRAPH_SLEEP_TIME))
return;
ftimes->calltime += current->ftrace_sleeptime - ftimes->sleeptime;
@@ -364,7 +372,7 @@ void trace_graph_return(struct ftrace_graph_ret *trace,
if (!ftimes)
return;
- handle_nosleeptime(trace, ftimes, size);
+ handle_nosleeptime(tr, trace, ftimes, size);
calltime = ftimes->calltime;
@@ -377,6 +385,7 @@ static void trace_graph_thresh_return(struct ftrace_graph_ret *trace,
struct ftrace_regs *fregs)
{
struct fgraph_times *ftimes;
+ struct trace_array *tr;
int size;
ftrace_graph_addr_finish(gops, trace);
@@ -390,7 +399,8 @@ static void trace_graph_thresh_return(struct ftrace_graph_ret *trace,
if (!ftimes)
return;
- handle_nosleeptime(trace, ftimes, size);
+ tr = gops->private;
+ handle_nosleeptime(tr, trace, ftimes, size);
if (tracing_thresh &&
(trace_clock_local() - ftimes->calltime < tracing_thresh))
@@ -452,6 +462,9 @@ static int graph_trace_init(struct trace_array *tr)
if (!tracer_flags_is_set(tr, TRACE_GRAPH_PRINT_IRQS))
ftrace_graph_skip_irqs++;
+ if (!tracer_flags_is_set(tr, TRACE_GRAPH_SLEEP_TIME))
+ fgraph_no_sleep_time++;
+
/* Make gops functions visible before we start tracing */
smp_mb();
@@ -494,6 +507,11 @@ static void graph_trace_reset(struct trace_array *tr)
if (WARN_ON_ONCE(ftrace_graph_skip_irqs < 0))
ftrace_graph_skip_irqs = 0;
+ if (!tracer_flags_is_set(tr, TRACE_GRAPH_SLEEP_TIME))
+ fgraph_no_sleep_time--;
+ if (WARN_ON_ONCE(fgraph_no_sleep_time < 0))
+ fgraph_no_sleep_time = 0;
+
tracing_stop_cmdline_record();
unregister_ftrace_graph(tr->gops);
}
@@ -1619,8 +1637,24 @@ void graph_trace_close(struct trace_iterator *iter)
static int
func_graph_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
{
- if (bit == TRACE_GRAPH_SLEEP_TIME)
- ftrace_graph_sleep_time_control(set);
+/*
+ * The function profiler gets updated even if function graph
+ * isn't the current tracer. Handle it separately.
+ */
+#ifdef CONFIG_FUNCTION_PROFILER
+ if (bit == TRACE_GRAPH_SLEEP_TIME && (tr->flags & TRACE_ARRAY_FL_GLOBAL) &&
+ !!set == fprofile_no_sleep_time) {
+ if (set) {
+ fgraph_no_sleep_time--;
+ if (WARN_ON_ONCE(fgraph_no_sleep_time < 0))
+ fgraph_no_sleep_time = 0;
+ fprofile_no_sleep_time = false;
+ } else {
+ fgraph_no_sleep_time++;
+ fprofile_no_sleep_time = true;
+ }
+ }
+#endif
/* Do nothing if the current tracer is not this tracer */
if (tr->current_trace != &graph_trace)
@@ -1630,6 +1664,16 @@ func_graph_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
if (!!set == !!(tr->current_trace_flags->val & bit))
return 0;
+ if (bit == TRACE_GRAPH_SLEEP_TIME) {
+ if (set) {
+ fgraph_no_sleep_time--;
+ if (WARN_ON_ONCE(fgraph_no_sleep_time < 0))
+ fgraph_no_sleep_time = 0;
+ } else {
+ fgraph_no_sleep_time++;
+ }
+ }
+
if (bit == TRACE_GRAPH_PRINT_IRQS) {
if (set)
ftrace_graph_skip_irqs--;
--
2.51.0
next prev parent reply other threads:[~2025-11-14 19:23 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-11-14 19:22 [PATCH 0/4] tracing: Make more function graph tracer options per-instance Steven Rostedt
2025-11-14 19:22 ` [PATCH 1/4] tracing: Have function graph tracer option funcgraph-irqs be per instance Steven Rostedt
2025-11-14 19:22 ` [PATCH 2/4] tracing: Move graph-time out of function graph options Steven Rostedt
2025-11-14 19:22 ` Steven Rostedt [this message]
2025-11-14 19:22 ` [PATCH 4/4] tracing: Convert function graph set_flags() to use a switch() statement Steven Rostedt
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20251114192318.950255167@kernel.org \
--to=rostedt@kernel.org \
--cc=akpm@linux-foundation.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-trace-kernel@vger.kernel.org \
--cc=mark.rutland@arm.com \
--cc=mathieu.desnoyers@efficios.com \
--cc=mhiramat@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.