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authorDaniel Bristot de Oliveira <bristot@kernel.org>2021-10-15 17:07:49 +0200
committerSteven Rostedt (VMware) <rostedt@goodmis.org>2021-10-26 05:02:36 +0200
commit4d4eac7b5af4c627cdab50c9e3b7bd19c4a144c6 (patch)
tree8adf6d9401b3b3ec3eea73cb5fb39ef49b9d83a0 /Documentation/trace
parenttrace/osnoise: Fix an ifdef comment (diff)
downloadlinux-4d4eac7b5af4c627cdab50c9e3b7bd19c4a144c6.tar.xz
linux-4d4eac7b5af4c627cdab50c9e3b7bd19c4a144c6.zip
tracing/doc: Fix typos on the timerlat tracer documentation
Fixes a series of typos in the timerlat doc. Link: https://lkml.kernel.org/r/d3763eb376603890baab908141de6660ba18fff8.1634308385.git.bristot@kernel.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> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'Documentation/trace')
-rw-r--r--Documentation/trace/timerlat-tracer.rst24
1 files 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,