From: Korben Rusek <korben@google.com>
To: Steven Rostedt <rostedt@goodmis.org>,
Ingo Molnar <mingo@redhat.com>, Jonathan Corbet <corbet@lwn.net>
Cc: Peter Shier <pshier@google.com>,
linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
jbehmer@google.com, franksie@google.com,
Korben Rusek <korben@google.com>
Subject: [PATCH 0/2] force absolute timestamp trace option
Date: Thu, 18 Jun 2020 15:15:39 -0700 [thread overview]
Message-ID: <20200618221541.247643-1-korben@google.com> (raw)
Normally a data event includes the delta time between itself and
the previous data event. But if a write interrupts another write
then the event cannot check the timestamp of the previous event
and so it uses a delta of 0.
Adds a new trace option: force-abs-timestamp. When this is on
each event is proceeded by an absolute timestamp event.
This follows from a discussion between jbehmer@google.com
and Steven Rostedt found here:
https://lkml.org/lkml/2019/5/24/710
Korben Rusek (2):
Add force-abs-timestamp trace option.
tests for absolute timestamp
Documentation/trace/ftrace.rst | 5 +
kernel/trace/trace.c | 4 +
kernel/trace/trace.h | 1 +
tools/testing/selftests/Makefile | 1 +
tools/testing/selftests/timestamp/Makefile | 25 +++
tools/testing/selftests/timestamp/abs-test.sh | 156 ++++++++++++++
.../selftests/timestamp/abs-timestamp.c | 198 ++++++++++++++++++
7 files changed, 390 insertions(+)
create mode 100644 tools/testing/selftests/timestamp/Makefile
create mode 100644 tools/testing/selftests/timestamp/abs-test.sh
create mode 100644 tools/testing/selftests/timestamp/abs-timestamp.c
--
2.27.0.290.gba653c62da-goog
next reply other threads:[~2020-06-18 22:16 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-18 22:15 Korben Rusek [this message]
2020-06-18 22:15 ` [PATCH 1/2] Add force-abs-timestamp trace option Korben Rusek
2020-06-18 22:15 ` [PATCH 2/2] tests for absolute timestamp Korben Rusek
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