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

From: Mark Rutland
Date: Thu Mar 02 2023 - 12:18:08 EST


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(-)

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2.30.2