[PATCH 0/4] trace: osnoise and timerlat fixes

[PATCH 0/4] trace: osnoise and timerlat fixes

[Daniel Bristot de Oliveira]

Hi Steven,

This is a series of minor fixes to the timerlat and osnoise tracers.

It includes a review of the timerlat tracer documentation, the addition of
the migrate disabled field to the timerlat and osnoise headers, and a
fix of a typo in the ifdef config comment in arch/x86/kernel/trace.c.

No functional changes.

Daniel Bristot de Oliveira (4):
  trace/osnoise: Fix an ifdef comment
  tracing/doc: Fix typos on the timerlat tracer documentation
  trace/osnoise: Add migrate-disabled field to the osnoise header
  trace/timerlat: Add migrate-disabled field to the timerlat header

 Documentation/trace/timerlat-tracer.rst | 24 ++++++++++++------------
 arch/x86/kernel/trace.c                 |  2 +-
 kernel/trace/trace_osnoise.c            | 25 +++++++++++++------------
 3 files changed, 26 insertions(+), 25 deletions(-)

-- 
2.31.1

[PATCH 1/4] trace/osnoise: Fix an ifdef comment

[Daniel Bristot de Oliveira]

s/CONFIG_OSNOISE_TRAECR/CONFIG_OSNOISE_TRACER/

No functional changes.

Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: x86@kernel.org
Cc: linux-doc@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
---
 arch/x86/kernel/trace.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/trace.c b/arch/x86/kernel/trace.c
index 6b73b6f92ad3..8322e8352777 100644
--- a/arch/x86/kernel/trace.c
+++ b/arch/x86/kernel/trace.c
@@ -231,4 +231,4 @@ void osnoise_arch_unregister(void)
 	unregister_trace_local_timer_exit(trace_intel_irq_exit, "local_timer");
 	unregister_trace_local_timer_entry(trace_intel_irq_entry, NULL);
 }
-#endif /* CONFIG_OSNOISE_TRAECR && CONFIG_X86_LOCAL_APIC */
+#endif /* CONFIG_OSNOISE_TRACER && CONFIG_X86_LOCAL_APIC */
-- 
2.31.1

[PATCH 2/4] tracing/doc: Fix typos on the timerlat tracer documentation

[Daniel Bristot de Oliveira]

Fixes a series of typos in the timerlat doc.

Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: x86@kernel.org
Cc: linux-doc@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Fixes: a955d7eac177 ("trace: Add timerlat tracer")
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
---
 Documentation/trace/timerlat-tracer.rst | 24 ++++++++++++------------
 1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/Documentation/trace/timerlat-tracer.rst b/Documentation/trace/timerlat-tracer.rst
index c7cbb557aee7..64d1fe6e9b93 100644
--- a/Documentation/trace/timerlat-tracer.rst
+++ b/Documentation/trace/timerlat-tracer.rst
@@ -3,7 +3,7 @@ Timerlat tracer
 ###############
 
 The timerlat tracer aims to help the preemptive kernel developers to
-find souces of wakeup latencies of real-time threads. Like cyclictest,
+find sources of wakeup latencies of real-time threads. Like cyclictest,
 the tracer sets a periodic timer that wakes up a thread. The thread then
 computes a *wakeup latency* value as the difference between the *current
 time* and the *absolute time* that the timer was set to expire. The main
@@ -50,14 +50,14 @@ The second is the *timer latency* observed by the thread. The ACTIVATION
 ID field serves to relate the *irq* execution to its respective *thread*
 execution.
 
-The *irq*/*thread* splitting is important to clarify at which context
+The *irq*/*thread* splitting is important to clarify in which context
 the unexpected high value is coming from. The *irq* context can be
-delayed by hardware related actions, such as SMIs, NMIs, IRQs
-or by a thread masking interrupts. Once the timer happens, the delay
+delayed by hardware-related actions, such as SMIs, NMIs, IRQs,
+or by thread masking interrupts. Once the timer happens, the delay
 can also be influenced by blocking caused by threads. For example, by
-postponing the scheduler execution via preempt_disable(), by the
-scheduler execution, or by masking interrupts. Threads can
-also be delayed by the interference from other threads and IRQs.
+postponing the scheduler execution via preempt_disable(), scheduler
+execution, or masking interrupts. Threads can also be delayed by the
+interference from other threads and IRQs.
 
 Tracer options
 ---------------------
@@ -68,14 +68,14 @@ directory. The timerlat configs are:
 
  - cpus: CPUs at which a timerlat thread will execute.
  - timerlat_period_us: the period of the timerlat thread.
- - osnoise/stop_tracing_us: stop the system tracing if a
+ - stop_tracing_us: stop the system tracing if a
    timer latency at the *irq* context higher than the configured
    value happens. Writing 0 disables this option.
  - stop_tracing_total_us: stop the system tracing if a
-   timer latency at the *thread* context higher than the configured
+   timer latency at the *thread* context is higher than the configured
    value happens. Writing 0 disables this option.
- - print_stack: save the stack of the IRQ ocurrence, and print
-   it afte the *thread context* event".
+ - print_stack: save the stack of the IRQ occurrence, and print
+   it after the *thread context* event".
 
 timerlat and osnoise
 ----------------------------
@@ -95,7 +95,7 @@ For example::
       timerlat/5-1035    [005] .......   548.771104: #402268 context thread timer_latency     39960 ns
 
 In this case, the root cause of the timer latency does not point to a
-single cause, but to multiple ones. Firstly, the timer IRQ was delayed
+single cause but to multiple ones. Firstly, the timer IRQ was delayed
 for 13 us, which may point to a long IRQ disabled section (see IRQ
 stacktrace section). Then the timer interrupt that wakes up the timerlat
 thread took 7597 ns, and the qxl:21 device IRQ took 7139 ns. Finally,
-- 
2.31.1

[PATCH 3/4] trace/osnoise: Add migrate-disabled field to the osnoise header

[Daniel Bristot de Oliveira]

Since "54357f0c9149 tracing: Add migrate-disabled counter to tracing
output," the migrate disabled field is also printed in the !PREEMPR_RT
kernel config. While this information was added to the vast majority of
tracers, osnoise and timerlat were not updated (because they are new
tracers).

Fix osnoise header by adding the information about migrate disabled.

Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: x86@kernel.org
Cc: linux-doc@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Fixes: 54357f0c9149 ("tracing: Add migrate-disabled counter to tracing output.")
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
---
 kernel/trace/trace_osnoise.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/kernel/trace/trace_osnoise.c b/kernel/trace/trace_osnoise.c
index ce053619f289..85852819aa0f 100644
--- a/kernel/trace/trace_osnoise.c
+++ b/kernel/trace/trace_osnoise.c
@@ -294,19 +294,19 @@ static void print_osnoise_headers(struct seq_file *s)
 	seq_puts(s, "#                                _-----=> irqs-off\n");
 	seq_puts(s, "#                               / _----=> need-resched\n");
 	seq_puts(s, "#                              | / _---=> hardirq/softirq\n");
-	seq_puts(s, "#                              || / _--=> preempt-depth     ");
-	seq_puts(s, "                       MAX\n");
-
-	seq_puts(s, "#                              || /                         ");
+	seq_puts(s, "#                              || / _--=> preempt-depth\n");
+	seq_puts(s, "#                              ||| / _-=> migrate-disable     ");
+	seq_puts(s, "                    MAX\n");
+	seq_puts(s, "#                              |||| /     delay               ");
 	seq_puts(s, "                    SINGLE      Interference counters:\n");
 
-	seq_puts(s, "#                              ||||               RUNTIME   ");
+	seq_puts(s, "#                              |||||               RUNTIME   ");
 	seq_puts(s, "   NOISE  %% OF CPU  NOISE    +-----------------------------+\n");
 
-	seq_puts(s, "#           TASK-PID      CPU# ||||   TIMESTAMP    IN US    ");
+	seq_puts(s, "#           TASK-PID      CPU# |||||   TIMESTAMP    IN US    ");
 	seq_puts(s, "   IN US  AVAILABLE  IN US     HW    NMI    IRQ   SIRQ THREAD\n");
 
-	seq_puts(s, "#              | |         |   ||||      |           |      ");
+	seq_puts(s, "#              | |         |   |||||      |           |      ");
 	seq_puts(s, "       |    |            |      |      |      |      |      |\n");
 }
 #endif /* CONFIG_PREEMPT_RT */
-- 
2.31.1

[PATCH 4/4] trace/timerlat: Add migrate-disabled field to the timerlat header

[Daniel Bristot de Oliveira]

Since "54357f0c9149 tracing: Add migrate-disabled counter to tracing
output," the migrate disabled field is also printed in the !PREEMPR_RT
kernel config. While this information was added to the vast majority of
tracers, osnoise and timerlat were not updated (because they are new
tracers).

Fix timerlat header by adding the information about migrate disabled.

Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: x86@kernel.org
Cc: linux-doc@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Fixes: 54357f0c9149 ("tracing: Add migrate-disabled counter to tracing output.")
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
---
 kernel/trace/trace_osnoise.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/kernel/trace/trace_osnoise.c b/kernel/trace/trace_osnoise.c
index 85852819aa0f..72765bf360ce 100644
--- a/kernel/trace/trace_osnoise.c
+++ b/kernel/trace/trace_osnoise.c
@@ -378,11 +378,12 @@ static void print_timerlat_headers(struct seq_file *s)
 	seq_puts(s, "#                               / _----=> need-resched\n");
 	seq_puts(s, "#                              | / _---=> hardirq/softirq\n");
 	seq_puts(s, "#                              || / _--=> preempt-depth\n");
-	seq_puts(s, "#                              || /\n");
-	seq_puts(s, "#                              ||||             ACTIVATION\n");
-	seq_puts(s, "#           TASK-PID      CPU# ||||   TIMESTAMP    ID     ");
-	seq_puts(s, "       CONTEXT                LATENCY\n");
-	seq_puts(s, "#              | |         |   ||||      |         |      ");
+	seq_puts(s, "#                              ||| / _-=> migrate-disable\n");
+	seq_puts(s, "#                              |||| /     delay\n");
+	seq_puts(s, "#                              |||||            ACTIVATION\n");
+	seq_puts(s, "#           TASK-PID      CPU# |||||   TIMESTAMP   ID      ");
+	seq_puts(s, "      CONTEXT                 LATENCY\n");
+	seq_puts(s, "#              | |         |   |||||      |         |      ");
 	seq_puts(s, "            |                       |\n");
 }
 #endif /* CONFIG_PREEMPT_RT */
-- 
2.31.1