From: Kalesh Singh <kaleshsingh@google.com>
To: unlisted-recipients:; (no To-header on input)
Cc: surenb@google.com, hridya@google.com, namhyung@kernel.org,
kernel-team@android.com, rostedt@goodmis.org,
mhiramat@kernel.org, Kalesh Singh <kaleshsingh@google.com>,
Jonathan Corbet <corbet@lwn.net>, Ingo Molnar <mingo@redhat.com>,
Shuah Khan <shuah@kernel.org>, Tom Zanussi <zanussi@kernel.org>,
linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-kselftest@vger.kernel.org
Subject: [PATCH 2/4] tracing/histogram: Update division by 0 documentation
Date: Fri, 29 Oct 2021 11:33:28 -0700 [thread overview]
Message-ID: <20211029183339.3216491-3-kaleshsingh@google.com> (raw)
In-Reply-To: <20211029183339.3216491-1-kaleshsingh@google.com>
If the divisor is a constant and zero, the undeifned case can be
detected and an error returned instead of -1.
Signed-off-by: Kalesh Singh <kaleshsingh@google.com>
---
Documentation/trace/histogram.rst | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/Documentation/trace/histogram.rst b/Documentation/trace/histogram.rst
index 66ec972dfb78..859fd1b76c63 100644
--- a/Documentation/trace/histogram.rst
+++ b/Documentation/trace/histogram.rst
@@ -1766,7 +1766,8 @@ using the same key and variable from yet another event::
Expressions support the use of addition, subtraction, multiplication and
division operators (+-\*/).
-Note that division by zero always returns -1.
+Note if division by zero cannot be detected at parse time (i.e. the
+divisor is not a constant), the result will be -1.
Numeric constants can also be used directly in an expression::
--
2.33.1.1089.g2158813163f-goog
next prev parent reply other threads:[~2021-10-29 18:34 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-29 18:33 [PATCH 0/4] tracing/histogram: Division optimization and expression kselftests Kalesh Singh
2021-10-29 18:33 ` [PATCH v2 1/4] tracing/histogram: Optimize division by constants Kalesh Singh
2021-10-29 18:45 ` Steven Rostedt
2021-10-29 18:53 ` Kalesh Singh
2021-10-29 19:16 ` Kalesh Singh
2021-10-29 20:25 ` Steven Rostedt
2021-10-29 22:31 ` Kalesh Singh
2021-10-29 23:24 ` [PATCH v3] " Kalesh Singh
2021-10-29 18:33 ` Kalesh Singh [this message]
2021-10-29 18:33 ` [PATCH v3 3/4] tracing/histogram: Document hist trigger variables Kalesh Singh
2021-10-29 18:33 ` [PATCH v7 4/4] tracing/selftests: Add tests for hist trigger expression parsing Kalesh Singh
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