linux-kernel - [PATCH 0/2] tracing/hist: add a modulus operator

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Message-Id: <20230302171755.1821653-1-mark.rutland@arm.com>
Date:   Thu,  2 Mar 2023 17:17:53 +0000
From:   Mark Rutland <mark.rutland@....com>
To:     linux-kernel@...r.kernel.org
Cc:     linux-trace-kernel@...r.kernel.org, mark.rutland@....com,
        mhiramat@...nel.org, rostedt@...dmis.org, zanussi@...nel.org
Subject: [PATCH 0/2] tracing/hist: add a modulus operator

I've been analysing some usercopy code, and wanted to cpature the spread
of sizes and alignment of copies for a workload. I found that histrogram
triggers were great for cpaturing the size, but there's not currently a
way to capture the alignment short of recording the entire base pointer
and post-processing the histogram, which is less than ideal.

These patches add a modulus operator to histogram expressions, so which
allows the alignment of pointers to be captured directly.

The first patch is a preparatory refactoring to the expression parsing
code, and the second actually adds the new operator.

Thanks,
Mark.

Mark Rutland (2):
  tracing/hist: simplify contains_operator()
  tracing/hist: add modulus operator

 Documentation/trace/histogram.rst |   4 +-
 kernel/trace/trace_events_hist.c  | 109 ++++++++++++++++--------------
 2 files changed, 62 insertions(+), 51 deletions(-)

-- 
2.30.2